Oncology Flashcards
(736 cards)
1
Q
What is the purpose of evaluating a cytologic specimen obtained by fine-needle aspiration (FNA) in small animals?
A
To make a definitive diagnosis and potentially avoid surgical biopsy.
2
Q
What are the advantages of using fine-needle aspiration (FNA) over surgical biopsy?
A
Lower risks and costs associated with FNA.
3
Q
In the study of cytologic specimens, what percentage of cases showed complete agreement with histopathologic diagnosis?
A
Approximately 40%.
4
Q
What is the bias that can help clinicians when interpreting cytologic specimens?
A
Prior experience and history of the patient.
5
Q
What types of tissues are easily accessible for fine-needle aspiration (FNA)?
A
- Skin and subcutis
- Deep and superficial lymph nodes
- Spleen
- Liver
- Kidneys
- Lungs
- Thyroid
- Prostate
- Intracavitary masses
6
Q
When should sterile preparation be done for fine-needle aspiration (FNA)?
A
When aspirating organs or masses within body cavities.
7
Q
What is the ‘woodpecker technique’ in fine-needle aspiration (FNA)?
A
Reinsert the needle into the tissue/mass several times to core out small samples.
8
Q
What is a potential risk associated with fine-needle aspiration (FNA) in dogs with certain tumors?
A
Transplantation of tumor cells along the needle tract.
9
Q
How can superficial ulcerated masses be sampled?
A
By scraping their surface with a sterile scalpel blade or tongue depressor.
10
Q
What is the first step in making impression smears from surgical specimens?
A
Gently blot the tissue onto a gauze pad or paper towel.
11
Q
What are some staining techniques used for cytologic specimens?
A
- Rapid Romanowsky (e.g., Diff-Quik)
- New methylene blue (NMB)
- Wright stain
- Giemsa stain
12
Q
What is a key difference between Romanowsky stains and new methylene blue (NMB)?
A
Romanowsky stains provide better cellular detail but are more time-consuming.
13
Q
What are the six categories for classifying cytologic specimens?
A
- Normal tissue
- Hyperplasia/dysplasia
- Inflammation
- Neoplasia
- Cystic lesions
- Mixed cellular infiltrate
14
Q
What is a characteristic feature of epithelial tissues in cytologic samples?
A
Cells tend to cling together, forming clusters or sheets.
15
Q
What is a common characteristic of mesenchymal tissue cells?
A
They are typically spindle-shaped, polygonal, or oval with indistinct cytoplasmic boundaries.
16
Q
What characterizes the cytology of inflammatory processes?
A
Presence of inflammatory cells and debris.
17
Q
What types of cells predominate in acute versus chronic inflammatory processes?
A
- Acute: Granulocytes
- Chronic: Macrophages and lymphocytes
18
Q
What pathogens are frequently identified in cytologic specimens?
A
- Histoplasma
- Blastomyces
- Sporothrix
- Cryptococcus
- Coccidioides
- Aspergillus/Penicillium
- Toxoplasma
- Leishmania
- Mycobacterium
- Other rickettsial agents
- Bacteria
- Demodex
19
Q
What are malignant cells?
A
Cells that exhibit abnormal characteristics compared to normal cells, often associated with cancer.
Malignant cells are characterized by their high N:C ratio, delicate chromatin, and other distinct features.
20
Q
What is a normal nuclear-to-cytoplasmic (N:C) ratio?
A
A typical ratio indicating a balance between the size of the nucleus and the cytoplasm in healthy cells.
Normal cells usually have a normal N:C ratio, while malignant cells have a high N:C ratio.
21
Q
List the features of malignant cells.
A
- High N:C ratio
- Delicate chromatin pattern
- Multiple nucleoli
- Anisokaryosis
- Nuclear molding
- Morphologic homogeneity
- Pleomorphism
- Vacuolization
- Anisocytosis
- Multinucleated giant cells
- Phagocytic activity
- Heterotopia
These features help in identifying malignant cells under a microscope.
22
Q
What is pleomorphism?
A
The occurrence of cells in different stages of development or with varying shapes and sizes.
Pleomorphism is a common characteristic of malignant cells.
23
Q
Define anisokaryosis.
A
A condition where cells have nuclei of different sizes.
Anisokaryosis is often seen in malignant cells.
24
Q
What does heterotopia refer to in the context of malignant cells?
A
The presence of a cell type in an anatomical location where it is not normally found.
For example, epithelial cells may appear in lymph nodes due to metastasis from a carcinoma.
25
What are the three classifications of malignancies based on cytologic features?
* Carcinomas (epithelial)
* Sarcomas (mesenchymal)
* Round (or discrete) cell tumors
## Footnote
These classifications help in identifying the type of cancer based on the origin of the malignant cells.
26
What is the significance of vacuolization in malignant epithelial tumors?
It is a feature that may indicate malignancy in epithelial tumors.
## Footnote
Vacuolization is primarily observed in malignant cells.
27
True or False: Malignant cells typically exhibit a lower N:C ratio than normal cells.
False
## Footnote
Malignant cells exhibit a higher N:C ratio compared to normal cells.
28
Fill in the blank: Malignant cells may show _______ activity, indicating their ability to engulf other cells or debris.
phagocytic
## Footnote
This is an occasional feature of malignant cells.
29
What are the characteristic cell types most carcinomas are composed of?
Round or polygonal cells
## Footnote
These cells tend to cling together, forming clusters or large sheets.
30
What color is the cytoplasm typically in most adenocarcinomas?
Deep blue
## Footnote
Vacuolization is often evident in adenocarcinomas.
31
How do cytoplasmic boundaries appear in most carcinomas?
Difficult to recognize
## Footnote
Cells resemble a mass of protoplasm rather than individual cells.
32
What is a distinguishing feature of squamous cell carcinomas?
Cells usually appear individualized, can be irregular or polygonal
## Footnote
They have a deep blue cytoplasm and large vacuoles.
33
What is leukophagia in the context of squamous cell carcinomas?
Neoplastic cells frequently exhibit leukophagia
## Footnote
This refers to the ingestion of white blood cells by tumor cells.
34
What are the characteristics of nuclei in adenocarcinomas and squamous cell carcinomas?
Large nuclei with a fine chromatin pattern and evident nucleoli
## Footnote
These features are common in both carcinoma types.
35
What is a general characteristic of sarcomas regarding exfoliation?
Sarcomas do not exfoliate well
## Footnote
However, some types like hemangiopericytomas exfoliate well.
36
What cell shapes are commonly found in mesenchymal tumors?
Spindle-shaped, polygonal, polyhedral, or oval cells
## Footnote
These cells typically have reddish-blue to dark blue cytoplasm.
37
What is the appearance of nuclei in most sarcomas?
Irregularly shaped nuclei
## Footnote
Nuclei often protrude from the cytoplasm.
38
What is suggestive of hemangiosarcoma in cytologic features?
Presence of spindle-shaped or polygonal cells with a vacuolated blue-gray cytoplasm
## Footnote
This is a key indicator in diagnosis.
39
What types of intercellular matrix can be found in osteosarcomas and chondrosarcomas?
Osteoid in osteosarcomas and chondroid in chondrosarcomas
## Footnote
Cells in these tumor types are usually round or ovoid.
40
What is the preferred approach for evaluating lytic bone lesions?
Perform an FNA (Fine Needle Aspiration)
## Footnote
It has a higher probability of obtaining a definitive diagnosis than a bone biopsy.
41
What is a common feature in some sarcomas in cats?
Presence of multinucleated giant cells
## Footnote
This is a notable characteristic in certain sarcomas.
42
What type of tumors are referred to as round (or discrete) cell tumors (RCTs)?
Tumors composed of a homogeneous population of round cells
## Footnote
Common in dogs and cats including lymphoma, histiocytoma, and malignant melanoma.
43
What aids in the classification of round cell tumors?
Presence or absence of cytoplasmic granules or vacuoles and the location of the nucleus
## Footnote
Cytology is key for diagnosis.
44
What color are cytoplasmic granules in MCTs when stained?
Purple
## Footnote
Granules in other tumors vary in color.
45
Do lymphomas, histiocytomas, plasma cell tumors, and transmissible venereal tumors have cytoplasmic granules?
No, they do not have cytoplasmic granules
## Footnote
This distinguishes them from other round cell tumors.
46
What is a characteristic of cells in osteosarcoma regarding granules?
Occasionally have small to large pink cytoplasmic granules (osteoid)
## Footnote
This can help in differentiating from other tumor types.
47
What type of tumors commonly have cytoplasmic vacuoles?
Transmissible venereal tumors (TVTs) and histiocytomas (HCTs)
## Footnote
This is a notable feature in their cytology.
48
What characterizes large cell LSAs?
Monomorphic population of poorly differentiated round cells with large nuclei, coarse chromatin pattern, and one or two nucleoli.
## Footnote
Occasional cells may be vacuolated.
49
How do cells in HCTs differ from those in lymphomas?
HCT cells have fine chromatin pattern, more abundant cytoplasm, and are frequently vacuolated.
## Footnote
Inflammatory cells like neutrophils and lymphocytes are also commonly found.
50
What distinguishes MCTs from other tumors?
Cytoplasm of neoplastic cells contains purple (metachromatic) granules, which may obscure nuclear features.
## Footnote
Eosinophils are also a common feature in these tumors.
51
What is the cytologic diagnosis rate for lymphadenopathy in dogs and cats?
Approximately 90% in dogs and 60% to 70% in cats.
## Footnote
If inconclusive, the lymph node should be surgically excised for histopathologic evaluation.
52
What are the four recognized cytologic patterns in lymph node evaluation?
* Normal lymph node
* Reactive or hyperplastic lymphadenopathy
* Lymphadenitis
* Neoplasia
53
What is the composition of cytologic specimens from normal lymph nodes?
Predominantly small lymphocytes (≈70% to 90%), approximately 7 to 10 µm in diameter, with dense chromatin pattern and no nucleoli.
## Footnote
Remaining cells include macrophages, lymphoblasts, plasma cells, and other immune cells.
54
What is observed in reactive or hyperplastic lymphadenopathy?
A mixture of small, intermediate, and large lymphocytes; lymphoblasts; plasma cells; and macrophages.
## Footnote
Presence of cells in different stages of development indicates polyclonal expansion.
55
What cytologic changes are seen in lymphadenitis?
Profusion of bloodborne inflammatory cells and degenerative changes (e.g., pyknosis, karyorrhexis).
## Footnote
Etiologic agents may be visualized.
56
How do neoplastic cells appear in lymph nodes?
Can result from lymphatic or vascular dissemination, or as a primary process (lymphomas).
## Footnote
Cytologic features include a reactive pattern and presence of neoplastic cells.
57
What is the morphology of metastatic cells in lymph nodes?
Dependent on the primary tumor type, often with an abnormally low N:C ratio, coarse chromatin, and evident nucleoli.
## Footnote
Advanced metastatic lesions may obscure normal lymphoid cells.
58
What is the simplest approach to classify lymph node cytologically?
Determine if the cell population is homogeneous (>70% resembling one another) or heterogeneous.
## Footnote
Homogeneous indicates normal node or neoplastic; heterogeneous indicates reactive, inflammatory, or early neoplastic.
59
What is the main cause of death in dogs?
Cancer
## Footnote
Cancer is also possibly a leading cause of death in cats.
60
In which dog breeds is cancer responsible for 60% of deaths?
Golden Retrievers and retired racing Greyhounds
61
What was the mainstay of cancer treatment for pets until 2 or 3 decades ago?
Surgery
62
What types of malignancies can be treated today with varied degrees of success?
Nonresectable or metastatic malignancies
63
True or False: Surgery is still the only treatment option for cancer in pets today.
False
64
What is a common choice for pet owners when their pet is diagnosed with cancer?
Owners will elect to treat their pets
## Footnote
Euthanasia remains a reasonable choice in some small animals with cancer, but treatment options should be investigated.
65
What percentage of human cancer patients have a life expectancy of at least 5 years?
More than 60%
## Footnote
This statistic includes patients with high-grade lymphoma, some acute leukemias, and some carcinomas and sarcomas who are cured.
66
What philosophical difference exists between treating cancer in humans versus pets?
The concept of cure
## Footnote
In humans, cure is a goal despite toxicity and expenses, while in pets, quality of life drives treatment decisions.
67
What drives the treatment decisions for pets with cancer according to the author's clinic?
Quality of life (QOL)
## Footnote
Treatment choices are influenced by the patient's condition and family perspectives.
68
What factors influence the selection of optimal treatment for a pet with cancer?
Tumor type, biologic behavior, clinical stage, patient-related, family-related, and treatment-related factors
## Footnote
These factors must be considered alongside tumor-related factors.
69
What is the most important patient-related factor when considering cancer treatment for a pet?
Animal's general health and activity or performance status
## Footnote
For example, a pet with poor performance status may not be a good candidate for aggressive treatment.
70
What statement does the author make regarding age as a factor in cancer therapy?
Age is not a disease
## Footnote
A healthy older dog may be a better candidate for treatment than a younger dog with chronic health issues.
71
What should be addressed before instituting specific cancer treatment in pets?
Patient-related factors
## Footnote
This may include correcting azotemia or improving nutritional status.
72
True or False: The best treatment for a tumor is always the best treatment for the patient.
False
## Footnote
The best treatment must also consider the patient's health and the family's perspective.
73
What role do family-related factors play in the treatment of pets with cancer?
They significantly influence the treatment approach based on the owner-pet bond and owner's willingness to proceed with treatment.
74
How can pet owners be involved in their pet's cancer treatment?
By performing tasks such as measuring the tumor, taking temperatures, and monitoring performance status.
75
What should clinicians do to support concerned pet owners?
Be available to answer questions and guide them through difficult times.
76
What factors should be discussed with pet owners regarding treatment options?
Pros and cons of each treatment option, including beneficial effects and potential adverse effects.
77
What is the significance of discussing potential adverse effects with pet owners?
It helps cultivate realistic expectations and ensures smooth interaction.
78
What should be the clinician's approach regarding treatment options?
All treatment options should be described and offered, regardless of cost.
79
What are the primary treatment-related factors to consider in cancer therapy?
Specific indication, combination of treatment modalities, complications, and adverse effects.
80
What is the goal of surgery and radiotherapy in cancer treatment?
To eradicate locally invasive tumors with low metastatic potential.
81
What is the typical role of chemotherapy in cancer treatment?
Usually palliative, not curative for advanced disease.
82
What is the benefit of combining surgery and chemotherapy?
Significantly prolongs disease-free survival.
83
What is the motto regarding patient quality of life during treatment?
"The patient should feel better with the treatment than with the disease."
84
What are the two main goals of treatment if a cure cannot be obtained?
To induce remission while achieving a good quality of life.
85
What does the term 'remission' refer to in cancer treatment?
Shrinkage of the tumor.
86
What criteria have veterinary oncologists adopted for evaluating therapy effects?
RECIST (response evaluation criteria in solid tumors).
87
True or False: Malignant tumors can regress spontaneously.
False.
88
What should be avoided to increase the likelihood of a cure in cancer treatment?
A wait-and-see attitude.
89
What is the purpose of metronomic chemotherapy?
To keep the tumor at bay while preserving the patient's QOL
90
What percentage of pet owners reported that their pets' QOL was maintained or improved during chemotherapy?
More than 80%
91
What should be done if a patient's performance status deteriorates?
The treatment should be modified or discontinued
92
What is one benefit of chemotherapy for pets with cancer?
Prolonged, good-quality survival
93
What common palliative surgery is mentioned for dogs or cats with ulcerated mammary carcinomas?
Mastectomy or lumpectomy
94
What is the survival time range for dogs with metastatic apocrine gland adenocarcinoma of the anal sacs after treatment?
1 to 3 years
95
What paraneoplastic syndrome treatment improves QOL in affected dogs?
Treatment of hypercalcemia of malignancy with bisphosphonates
96
What are the dosages for pamidronate and zoledronate in treating tumor-associated hypercalcemia in dogs?
* Pamidronate: 1-2 mg/kg, IV q6-8 weeks
* Zoledronate: 0.1 mg/kg, IV q3-8 weeks
97
What has contributed markedly to improving the QOL in small animal cancer patients?
Pain control with opioids, nonsteroidal anti-inflammatories, and other drugs
98
What is necessary to understand the effects of chemotherapy on tissues?
A basic understanding of cell biology and tumor kinetics
## Footnote
This includes the similarities and differences between neoplastic and normal cells.
99
How do neoplastic cells differ from normal cells regarding differentiation?
Neoplastic cells usually do not undergo terminal differentiation or apoptosis
## Footnote
Apoptosis is programmed cell death.
100
What are the original hallmarks of cancer according to Hanahan and Weinberg?
* Sustaining proliferative signaling
* Evading growth suppressors
* Resisting cell death
* Enabling replicative immortality
* Inducing angiogenesis
* Activating invasion and metastasis
## Footnote
These hallmarks provide a framework for understanding cancer cell biology.
101
What is the significance of genome instability in cancer cells?
It generates genetic diversity that expedites the acquisition of hallmark traits
## Footnote
This instability is a key factor in cancer progression.
102
What role does inflammation play in cancer according to recent research?
It fosters multiple hallmark functions in cancer
## Footnote
Inflammation is linked to the progression and maintenance of cancer characteristics.
103
What are the two emerging hallmarks of cancer that were added recently?
* Reprogramming of energy metabolism
* Evading immune destruction
## Footnote
These hallmarks represent new understandings of cancer biology.
104
What is the tumor microenvironment?
A repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits
## Footnote
This environment plays a crucial role in tumor development and progression.
105
What are the two apparent phases of the mammalian cell cycle?
* Mitosis
* Resting phase
## Footnote
The resting phase is actually composed of four phases.
106
True or False: The cell cycles of normal and neoplastic cells are fundamentally different.
False
## Footnote
The cell cycles are similar, but the behavior of neoplastic cells differs in critical ways.
107
What occurs during the synthesis phase (S)?
DNA is synthesized
108
What happens during the Gap 1 phase (G1)?
RNA and the enzymes needed for DNA production are synthesized
109
What is formed during the Gap 2 phase (G2)?
The mitotic spindle apparatus forms
110
What is the true resting phase of the cell cycle called?
Gap 0 phase (G0)
111
What is the term for the mitosis phase in the cell cycle?
M phase
112
What role do oncogenes play in the cell cycle?
Serve as checkpoints between different phases of the cell cycle
113
What does the mitotic index (MI) refer to?
The proportion of cells in the process of mitosis within a tumor
114
How is the mitotic activity in a tumor sample often reported?
As the MI or as the number of mitoses per high-power field
115
What does the growth fraction (GF) indicate?
The proportion of proliferating cells within a tumor
116
What is doubling time (DT)?
The time it takes for a tumor to double in size
117
How can doubling time (DT) be calculated?
Using sequential measurements of the tumor volume or determined by direct palpation
118
What is the range of doubling time (DT) for metastatic osteosarcoma in dogs?
2 days
119
What is the range of doubling time (DT) for metastatic melanoma in dogs?
24 days
120
What is the range of doubling time (DT) for malignant lymphomas in humans?
29 days
121
What is the range of doubling time (DT) for metastases from breast cancer in humans?
83 days
122
What factors influence doubling time (DT)?
* Time spent in mitosis
* Cell cycle duration
* Growth fraction (GF)
* Cell loss from death or metastasis
123
What happens to a pulmonary metastatic nodule by the time it is visualized on radiographs?
It consists of more than 200 million cells and weighs less than 150 mg
124
How many tumor cells are in a 1-cm palpable nodule?
109 tumor cells (1 trillion)
125
What is the weight of a 1-cm palpable nodule?
1 g
126
What characteristics do most nonneoplastic tissues have compared to neoplastic tissues?
* Low growth fraction (GF)
* Low mitotic index (MI)
* Prolonged doubling time (DT)
127
What effect does surgical cytoreduction (debulking) of a tumor have?
* Decreases the total number of cells
* Increases the mitotic index (MI)
* Increases the growth fraction (GF)
* Shortens the doubling time (DT)
128
What is the theoretical benefit of surgical cytoreduction in relation to chemotherapy or radiotherapy?
It renders the neoplasm more susceptible to chemotherapy or radiotherapy
129
What types of tissues do chemotherapeutic agents predominantly kill?
Rapidly dividing tissues
## Footnote
This includes various cancerous tissues that are actively proliferating.
130
What is the common practice when using chemotherapeutic drugs to treat malignancies?
Combine three or more drugs
## Footnote
This approach enhances the tumoricidal effect and reduces the risk of resistance.
131
What are the three principles for selecting drugs in combination chemotherapy?
* Each should be active against the tumor type
* Act by a different mechanism of action
* Not have superimposed toxicities
## Footnote
These principles help maximize efficacy and minimize adverse effects.
132
What is the naming convention for chemotherapy protocols?
Named after the first letters of each drug in the combination
## Footnote
Example: VAC for vincristine, doxorubicin, and cyclophosphamide.
133
What are the benefits of combination chemotherapy compared to single-agent chemotherapy?
More sustained remissions and prolonged survival times
## Footnote
This is due to the delay or prevention of drug-resistant clones.
134
In what cases can single-agent chemotherapy be as effective as multiagent chemotherapy?
* Carboplatin or doxorubicin in dogs with osteosarcoma
* Chlorambucil for dogs with chronic lymphocytic leukemia
* Vincristine for dogs with transmissible venereal tumors
## Footnote
These examples demonstrate effective single-agent treatments with less toxicity.
135
How does tumor size affect the effectiveness of chemotherapy?
More effective in a relatively small tumor than in a large one
## Footnote
Smaller tumors have a higher mitotic index, growth fraction, and shorter doubling time.
136
What parameters are compared in chemotherapy effectiveness based on tumor size?
* Higher mitotic index (MI)
* Higher growth fraction (GF)
* Shorter doubling time (DT)
## Footnote
These factors contribute to the likelihood of complete eradication of smaller tumors.
137
On what basis are doses of most chemotherapeutic agents still determined?
Body surface area (BSA) basis
## Footnote
This method provides a constant metabolic parameter for dose comparison across species.
138
What is the formula used to calculate body surface area (BSA)?
BSA = √((height in cm × weight in kg) / 3600)
## Footnote
This formula helps standardize dosing across different animals.
139
What is chemotherapy primarily indicated for in animals?
Chemotherapy is primarily indicated for systemic or metastatic neoplasms, nonresectable chemoresponsive neoplasms, and as an adjuvant treatment after surgical debulking.
140
What is the role of chemotherapy after surgical excision of primary neoplasms?
Chemotherapy is indicated for the control of micrometastatic disease after surgical excision.
141
Which drugs are examples of chemotherapy used after limb amputation in dogs with osteosarcoma?
Carboplatin or doxorubicin therapy.
142
What is the purpose of administering chemotherapy intracavitarily in pets?
To treat malignant effusions or neoplastic involvement of a cavity.
143
Fill in the blank: Chemotherapy is generally considered to be _______ in pets with cancer.
palliative
144
What is a significant difference in chemotherapy dosing between pets and humans?
Pets receive much lower doses compared to humans, e.g., cyclophosphamide doses are rarely higher than 300 mg/m2 in dogs, while humans may use 2 to 3 g/m2.
145
True or False: Chemotherapy can be used as a substitute for surgery or radiotherapy.
False
146
What should be considered before using chemotherapy in animals with severe underlying multiple-organ dysfunction?
It should be used cautiously, with a dose modification.
147
What principle do anticancer drugs follow regarding their effects on neoplastic cell populations?
First-order kinetic principles.
148
What do cell cycle phase-nonspecific drugs do?
They kill a constant proportion of cells, regardless of their cycle status.
149
Name an example of a cell cycle phase-nonspecific drug.
Alkylating agents.
150
What are cell cycle phase-specific drugs known for?
They selectively kill tumor cells during a specific phase of the cell cycle.
151
Most antimetabolites and plant alkaloids are classified as what type of drugs?
Cell cycle phase-specific drugs.
152
What characterizes cell cycle-nonspecific drugs?
They kill neoplastic cells regardless of their cycle status.
153
What is a notable side effect of cell cycle-nonspecific drugs?
They are extremely myelosuppressive.
154
Fill in the blank: A drug combination that kills 99% of the cells in a tumor containing 100 million cells leaves _______ viable cells.
1 million
155
What is the mechanism of action of alkylating agents?
Cross-link DNA, preventing its duplication
## Footnote
They are also referred to as radiomimetics.
156
During which phases of the cell cycle are alkylating agents most active?
Cell cycle phase-nonspecific
## Footnote
They are more active if given intermittently at high doses.
157
What are the major toxicities associated with alkylating agents?
* Myelosuppression
* Gastrointestinal toxicity
158
What type of agents exert their activity during the S phase of the cell cycle?
Antimetabolites
159
How do antimetabolites differ in their administration for effectiveness?
More active if given repeatedly at low doses or as continuous intravenous infusions
160
What are the major toxicities of antimetabolites?
* Myelosuppression
* Gastrointestinal toxicity
161
What is the primary mechanism of action of antitumor antibiotics?
DNA damage produced by free radicals or a topoisomerase-II–dependent mechanism
162
What are the major toxicities associated with antitumor antibiotics?
* Myelosuppression
* Gastrointestinal toxicity
163
Which two antitumor antibiotics are known to cause severe extravasation injuries if given perivascularly?
* Doxorubicin
* Actinomycin D
164
What is the source of plant alkaloids used in cancer treatment?
* Periwinkle plant (Vinca rosea)
* May apple plant (Podophyllum peltatum)
165
What is the primary toxicity associated with Vinca derivatives?
Perivascular sloughing if the agent extravasates
166
What is the role of corticosteroids in cancer treatment?
Treatment of hemolymphatic malignancies, mast cell tumors, and brain tumors
167
What defines miscellaneous agents in cancer chemotherapy?
Drugs with a mechanism of action that is either unknown or differs from previously described agents
168
What are tyrosine kinase inhibitors used for in cancer treatment?
To exploit molecular targets such as TK family receptors
169
Name two tyrosine kinase inhibitors that have been used in small animal patients.
* Toceranib (Palladia)
* Imatinib
170
What is metronomic chemotherapy?
Chronic administration of chemotherapeutic agents at relatively low, minimally toxic doses
171
What is the proposed main mechanism of action for metronomic chemotherapy?
Inhibition of tumor angiogenesis
172
What role do T-regulatory lymphocytes (TREG) play in cancer?
They correlate with tumor progression and lack of treatment response
173
How does low-dose cyclophosphamide affect TREG cells?
Decreases numbers and inhibits their suppressive functions
174
What is the recommended environment for reconstituting cytotoxic drugs?
Biosafety level II vertical laminar airflow hood
175
What personal protective gear is recommended for handling cytotoxic drugs?
* Thick latex chemotherapy gloves
* Impermeable disposable gowns
* Eye protection
* Particle-filtering face masks
176
What should be done with potentially contaminated materials used in chemotherapy?
Disposed of in properly labeled biohazard bags or plastic sharps containers
177
How long should patient waste be handled with precautions after chemotherapy administration?
24 to 48 hours
178
What should be prepared in advance for handling spills of cytotoxic drugs?
Protocols for handling spills
179
What should be done to indicate a patient has received chemotherapy?
The cage should be clearly identified with a notice about handling precautions
180
What is pancreatitis in relation to chemotherapy?
A well-recognized entity in human patients undergoing chemotherapy, with sporadic reports in dogs but not in cats.
## Footnote
Offending drugs include corticosteroids, azathioprine, and L-asparaginase.
181
What are the clinical signs of pancreatitis in dogs receiving chemotherapy?
Anorexia, vomiting, and depression.
## Footnote
Physical examination findings are usually unremarkable, and abdominal pain is rare.
182
How is chemotherapy-induced pancreatitis treated in dogs?
With IV fluids, and clinical signs typically resolve within 3 to 10 days.
## Footnote
A low-fat diet may be advised for dogs receiving pancreatitis-inducing drugs.
183
What is cardiotoxicity in relation to doxorubicin therapy?
A relatively uncommon complication in dogs, extremely rare in cats.
## Footnote
It includes acute reactions during administration and chronic cumulative toxicity.
184
What are the types of doxorubicin-induced cardiac toxicities observed in dogs?
Acute reaction and chronic cumulative toxicity.
## Footnote
Acute toxicity is characterized by cardiac arrhythmias, while chronic toxicity leads to dilated cardiomyopathy.
185
What is the hallmark of chronic doxorubicin toxicity?
Dilated cardiomyopathy developing after exceeding a total cumulative dose of approximately 240 mg/m2.
## Footnote
Histologic lesions include myocyte vacuolation.
186
What should be monitored in patients receiving doxorubicin to prevent cardiomyopathy?
Myocardial contractility and rhythm disturbances.
## Footnote
Echocardiographic evaluation every three doxorubicin cycles is recommended.
187
What is the recommended method to minimize doxorubicin-induced cardiomyopathy?
Administering doxorubicin slowly in a diluted solution over 30 minutes.
## Footnote
Dexrazoxane and carvedilol have also shown promise in reducing toxicity.
188
What are the two specific complications of anticancer agents affecting the urinary tract in pets?
Nephrotoxicity and sterile hemorrhagic cystitis.
## Footnote
Transitional cell carcinomas from chronic cyclophosphamide therapy have been reported in dogs.
189
Which anticancer agents are of concern for nephrotoxicity in dogs and cats?
Doxorubicin, cisplatin, and intermediate to high doses of methotrexate.
## Footnote
Doxorubicin can cause nephrotoxicosis, especially in cats.
190
What is sterile hemorrhagic cystitis (SHC) and its relation to cyclophosphamide?
A common complication of long-term cyclophosphamide therapy in dogs.
## Footnote
It can develop after a single dose and is caused by the caustic effects of cyclophosphamide metabolites.
191
What are the clinical signs of sterile hemorrhagic cystitis?
Pollakiuria, hematuria, and dysuria.
## Footnote
Urinalysis typically reveals blood and increased white blood cells but no bacteria.
192
What are the treatment options for sterile hemorrhagic cystitis in dogs?
Discontinuing cyclophosphamide, forcing diuresis, and anti-inflammatory treatment.
## Footnote
Furosemide and prednisone are commonly used.
193
What is the prevalence of hepatotoxicity in dogs receiving lomustine?
Low prevalence (<10%).
## Footnote
Marked increases in ALT and mild increases in ALP can occur within 3 weeks of starting therapy.
194
What is the risk of neurotoxicity associated with 5-FU in dogs?
Extremely rare, but can occur and is common in cats.
## Footnote
Clinical signs include excitation and cerebellar ataxia.
195
What is acute tumor lysis syndrome (ATLS)?
A syndrome characterized by hyperuricemia, hyperphosphatemia, and hyperkalemia after the rapid lysis of tumor cells.
## Footnote
It is rare in dogs and usually associated with lymphomas.
196
What are the potential consequences of acute tumor lysis syndrome in dogs?
Hyperphosphatemia, azotemia, hyperkalemia, hypocalcemia, metabolic acidosis, and hyperuricemia.
197
What is characterized by the release of high quantities of intracellular phosphate, uric acid, and nucleic acid metabolites?
Acute Tumor Lysis Syndrome (ATLS)
## Footnote
ATLS leads to significant metabolic disturbances due to rapid cell breakdown.
198
How much higher is the intracellular concentration of phosphorus in human lymphoma and leukemic cells compared to normal lymphocytes?
4 to 6 times higher
## Footnote
This elevated level is also observed in dogs.
199
In which species is ATLS reported to be rare?
Cats
## Footnote
Most ATLS cases are documented in dogs.
200
What are the clinical signs of ATLS in dogs?
Depression, vomiting, and diarrhea
## Footnote
These signs occur within hours of initiating chemotherapy.
201
What treatment modalities have been associated with the occurrence of ATLS in dogs?
Chemotherapy, radiation therapy, or both
## Footnote
ATLS occurs primarily in dogs with lymphoma undergoing these treatments.
202
What percentage of dogs treated with chemotherapy for lymphoma developed ATLS in the documented cases?
0.5%
## Footnote
10 cases were documented out of approximately 2000 treated dogs.
203
Within how many days did clinical signs develop in affected dogs after starting chemotherapy?
1 to 7 days
## Footnote
Signs included lethargy, vomiting, and bloody diarrhea.
204
What electrolyte disturbances are associated with ATLS?
Hyperphosphatemia, hyperkalemia, hypocalcemia
## Footnote
Metabolic acidosis and hyperuricemia may also occur.
205
What was the outcome for the majority of dogs treated for ATLS with aggressive fluid therapy?
Resolution of clinical signs within 3 days in 6 dogs
## Footnote
2 dogs died as a result of ATLS.
206
What laboratory finding was noted in most dogs before treatment for lymphoma?
High pretreatment serum creatinine concentrations
## Footnote
High tumor burden was also common.
207
Fill in the blank: ATLS is characterized by _______ with or without azotemia.
hyperphosphatemia
## Footnote
Azotemia refers to an excess of nitrogen-containing compounds in the blood.
208
What is more common in dogs and cats undergoing chemotherapy: delayed hair growth or alopecia?
Delayed hair growth
## Footnote
This contrasts with human patients, where severe scalp alopecia is a predictable complication of therapy.
209
What phase of the hair cycle is usually affected by chemotherapeutic agents?
Anagen (growth) phase
## Footnote
This affects rapidly dividing tissues, leading to slow hair regrowth.
210
Which breeds of dogs predominantly experience alopecia due to chemotherapy?
* Poodles
* Schnauzers
* Kerry Blue Terriers
## Footnote
Alopecia mainly affects the tactile hairs in short-haired dogs and cats.
211
Name some drugs commonly associated with delayed hair growth and alopecia.
* Cyclophosphamide
* Doxorubicin
* 5-FU
* 6-thioguanine
* Hydroxyurea
## Footnote
Alopecia and delayed hair growth usually resolve shortly after discontinuation of the offending agent.
212
Is hyperpigmentation common in dogs receiving chemotherapy?
No, it is uncommon in dogs and extremely rare in cats.
## Footnote
However, it can affect areas like the face, ventral abdomen, and flanks in dogs on doxorubicin- and bleomycin-containing protocols.
213
What are the three types of dermatologic toxicities that can occur in small animals receiving anticancer agents?
* Local tissue necrosis
* Delayed hair growth and alopecia
* Hyperpigmentation
## Footnote
These toxicities are rare but can occur with certain chemotherapeutic agents.
214
What is a potential consequence of local tissue necrosis in dogs receiving chemotherapy?
Extravasation
## Footnote
This is caused by drugs like vincristine, vinblastine, actinomycin D, doxorubicin, or Tanovea.
215
What should be done to minimize the probability of extravascular injection of caustic drugs?
Administer through small-gauge catheters
## Footnote
Use 22- to 23-gauge indwelling IV catheters or 23- to 25-gauge butterfly catheters.
216
What is the recommended concentration for diluting vincristine before administration?
0.1 mg/mL
## Footnote
Doxorubicin should be diluted to a concentration of 0.5 mg/mL.
217
How long does tissue necrosis from doxorubicin extravasation persist in tissues?
Up to 16 weeks
## Footnote
Doxorubicin is extremely caustic, leading to severe tissue damage.
218
What can be administered if doxorubicin is recognized to have been given perivascularly?
Dexrazoxane
## Footnote
It should be administered at 5 to 10 times the dose of doxorubicin given.
219
What clinical signs indicate extravasation of chemotherapy agents?
* Pain
* Pruritus
* Erythema
* Moist dermatitis
* Necrosis
## Footnote
Severe tissue sloughing may occur in affected areas.
220
What percentage of dogs may develop dermatologic toxicity when receiving Tanovea?
Up to 45%
## Footnote
This generally consists of pruritic, focal otitis externa or focal erythemic skin lesions.
221
True or False: Cats are more prone to develop local tissue necrosis from chemotherapy than dogs.
False
## Footnote
Local tissue necrosis is extremely rare in cats receiving chemotherapy.
222
What occurs first in the pathogenesis of sepsis in neutropenic animals?
Chemotherapy-induced death and desquamation of gastrointestinal crypt epithelial cells occur simultaneously with myelosuppression
223
What happens after enteric bacteria are translocated into the systemic circulation?
Multiple organs become colonized with the bacteria and death ensues unless treated appropriately
224
Why is it important to identify septic neutropenic patients using laboratory means?
Cardinal signs of inflammation may be absent due to insufficient neutrophils
225
What is the neutrophil count threshold for a severely neutropenic animal?
Neutrophil count <500/µL
226
What should be attributed to fever in a severely neutropenic animal?
Bacterial pyrogens until proved otherwise
227
What should all dogs and cats undergoing chemotherapy be up to date on?
Vaccines
228
What is the recommended frequency for obtaining complete blood counts (CBCs) in patients receiving chemotherapy?
Weekly or every other week
229
What should be done if the neutrophil count decreases to fewer than 1000 cells/µL?
Temporarily discontinue or decrease the myelosuppressive agent
230
What is the classification of neutropenic patients in clinical settings?
Febrile or afebrile
231
What is the emergency status of fever in a neutropenic patient?
Medical emergency
232
What is the empirical antibiotic combination used for neutropenic febrile patients?
* Enrofloxacin (5-10 mg/kg IV q24h) * Ampicillin (22 mg/kg IV q8h) or * Ampicillin/sulbactam (30 mg/kg IV q8h)
233
What is the prevalence of bacteremia in neutropenic episodes using 2 sets of blood cultures?
12.3% (7/57)
234
What are the main bacterial isolates found in neutropenic febrile dogs?
* Klebsiella spp. * E. coli * Staphylococcus spp. (isolated in <20% of dogs)
235
What should be done for afebrile, asymptomatic neutropenic patients?
Treat as outpatients by discontinuing the drug and administering appropriate antibiotics
236
What is the role of the intestinal microbiome in tumor immunomodulation?
It predicts the risk of sepsis and modifies the immunologic response against tumor antigens
237
What agents may alleviate myelosuppression in dogs?
* Lithium carbonate (10 mg/kg PO q12h) * Recombinant human granulocyte colony-stimulating factor (G-CSF; 5 µg/kg subcutaneously q24h)
238
What are the two major types of gastrointestinal complications from cancer chemotherapy?
* Anorexia * Nausea * Vomiting * Gastroenterocolitis
239
What drugs are associated with nausea and vomiting in pets?
* Dacarbazine * Cisplatin * Doxorubicin * Methotrexate * Actinomycin D * Cyclophosphamide * 5-fluorouracil
240
What is a preferred antiemetic for chemotherapy-associated nausea in pets?
Maropitant
241
What breeds are extremely susceptible to doxorubicin-induced enterocolitis?
* Collies * Old English Sheepdogs * Cocker Spaniels * West Highland White Terriers
242
What are the characteristics of doxorubicin-induced enterocolitis in dogs?
Hemorrhagic diarrhea (with or without vomiting) 3 to 7 days after administration
243
What is the treatment for doxorubicin-induced enterocolitis?
* Supportive fluid therapy * Therapeutic doses of bismuth subsalicylate-containing products
244
What type of hypersensitivity reactions can occur in dogs receiving certain anticancer agents?
Acute type I hypersensitivity reactions
245
What is the common clinical sign of hypersensitivity reactions in dogs?
Cutaneous and gastrointestinal signs
246
What type of reaction does doxorubicin induce?
Direct mast cell degranulation independently of immunoglobulin E (IgE) mediation
## Footnote
This indicates that the reaction is not a true hypersensitivity reaction.
247
Can etoposide be administered to dogs?
Yes, etoposide can be safely administered to dogs PO
## Footnote
PO stands for per os, meaning by mouth.
248
Are hypersensitivity reactions to anticancer agents common in cats?
No, they are extremely rare in cats
## Footnote
Thus, such reactions are not discussed.
249
What are typical clinical signs of hypersensitivity reactions in dogs?
Head shaking, generalized urticaria and erythema, restlessness, vomiting or diarrhea, collapse caused by hypotension
## Footnote
These signs are similar to those in other types of hypersensitivity reactions.
250
When do typical signs of hypersensitivity appear in dogs after administration of anticancer agents?
During or shortly after administration
## Footnote
This timing is crucial for recognizing the reaction.
251
What can help prevent most systemic anaphylactic reactions in dogs?
Pretreating with H1 antihistamines and administering certain drugs subcutaneously or intramuscularly
## Footnote
Example of H1 antihistamine: intramuscular diphenhydramine.
252
What is the recommended dose of diphenhydramine for pretreatment?
1-2 mg/kg 20-30 minutes before administration
## Footnote
This is for preventing hypersensitivity reactions.
253
What should be done if the agent cannot be given by any route other than IV?
It should be diluted and administered by slow IV infusion
## Footnote
This is particularly relevant for doxorubicin.
254
What is the first step in treating acute hypersensitivity reactions?
Immediate discontinuation of the agent
## Footnote
Following this, other treatments can be administered.
255
What medications are administered for acute hypersensitivity reactions?
H1 antihistamines, dexamethasone sodium phosphate, and fluids if necessary
## Footnote
H1 antihistamine example: diphenhydramine (0.2-0.5 mg/kg by slow IV infusion).
256
What is the dosage of epinephrine for severe systemic reactions?
0.1-0.3 mL of a 1:1000 solution intramuscularly or intravenously
## Footnote
This dosage is for emergency situations.
257
What should be done once a mild hypersensitivity reaction subsides?
The administration of certain drugs such as doxorubicin may be continued
## Footnote
This is contingent on the severity of the reaction.
258
Why should injectable H1 antihistamines be used with caution in cats?
They can cause acute central nervous system depression leading to apnea
## Footnote
This poses a significant risk in feline patients.
259
What is the mitotic rate and growth fraction of bone marrow cells?
40%-60%
## Footnote
This high rate predisposes the bone marrow to toxicity from anticancer drugs.
260
What is the most common complication of chemotherapy?
Hematologic toxicity
261
What can severe cytopenias from chemotherapy necessitate?
Temporary or permanent discontinuation of the offending agent or agents
262
How long is the bone marrow transit time for red blood cells in dogs?
Approximately 7 days
263
What is the circulating half-life of platelets in dogs?
4 to 6 days
264
What usually occurs first due to chemotherapy, neutropenia or thrombocytopenia?
Neutropenia
265
What is the typical onset time for chemotherapy-induced anemia in dogs?
3-4 months after initiation of therapy
266
What can cause iron deficiency anemia in dogs on chemotherapy?
Chronic gastrointestinal bleeding from gastroduodenal ulcers or erosions
267
What factors can affect the degree of myelosuppression?
* Malnutrition
* Old age
* Concurrent organ dysfunction
* Prior extensive chemotherapy
* Bone marrow infiltration
* Widespread parenchymal organ metastases
268
What platelet count is typically associated with spontaneous bleeding in dogs?
Below 30,000 cells/µL
269
Which drugs are associated with predictable thrombocytopenia in dogs?
* Doxorubicin
* Dacarbazine
* Lomustine
* Melphalan
270
Is chemotherapy-induced thrombocytopenia common in cats?
No, it is extremely rare
271
What is pseudothrombocytopenia?
Low platelet count with platelet aggregates on analyzer graphics or blood smear
272
What cytopenia usually constitutes the dose-limiting factor in chemotherapy?
Neutropenia
273
When does the nadir of neutropenia usually occur after chemotherapy treatment?
5 to 7 days
274
What neutrophil count should be closely monitored for the development of sepsis in dogs?
Less than 2000 cells/µL
275
What is the pathogenesis of sepsis in neutropenic animals?
* Death and desquamation of gastrointestinal crypt epithelial cells
* Translocation of enteric bacteria into systemic circulation
* Insufficient neutrophils to combat invading organisms
276
What might be absent in septic neutropenic patients due to low neutrophil counts?
Cardinal signs of inflammation
277
What should be attributed to bacterial pyrogens in severely neutropenic animals with fever?
The fever should be attributed until proved otherwise
278
What is a common radiographic finding in dogs with neutropenia and bacterial pneumonia?
Normal thoracic radiographic findings
279
What is the neutrophil count considered severely neutropenic?
Less than 500/µL
280
What is a potential symptom of neutropenic septic patients?
Hypothermia
281
What factors can potentiate the effects of anticancer agents?
Drugs excreted primarily through the kidneys, such as platinum compounds and methotrexate, can enhance toxicity in animals with renal disease
## Footnote
A dose reduction or alternative drug is usually recommended in such patients.
282
What is acute tumor lysis syndrome (ATLS)?
A syndrome caused by rapid killing of neoplastic cells leading to sudden metabolic derangements that mimic drug toxicity
## Footnote
It is extremely rare.
283
Which species appears to be more susceptible to chemotherapy adverse effects?
Cats appear to be more susceptible than dogs to some adverse effects of chemotherapy, such as anorexia and vomiting
## Footnote
However, dogs are not more susceptible to myelosuppression.
284
Which dog breeds are more prone to acute adverse reactions to chemotherapy?
Collies, Collie crosses, Old English Sheepdogs, Cocker Spaniels, and West Highland White Terriers
## Footnote
These breeds show more gastrointestinal signs and myelosuppression than the general dog population.
285
What gene mutation is associated with certain dog breeds and chemotherapy toxicity?
Mutations of the ABCB1 (formerly MDR1) gene, which encodes for P-glycoprotein
## Footnote
This efflux pump eliminates chemotherapeutic agents from the cytoplasm of the cells.
286
What is the overall prevalence of toxicity in dogs and cats treated with chemotherapy compared to humans?
The prevalence of toxicity in dogs and cats is approximately 5%-40%, while in humans it is 75%-100%
## Footnote
This is for similar drugs or combinations.
287
What percentage of pet owners considered their pets' quality of life to be as good as or better after chemotherapy?
More than 80% of owners reported their pets' quality of life was as good as or better than before chemotherapy
## Footnote
This was based on a survey at The Ohio State University Veterinary Medical Center.
288
What were the findings of the study at North Carolina State University regarding quality of life during chemotherapy?
77% of dogs and 66% of cats experienced no negative impact on their quality of life while undergoing chemotherapy
## Footnote
Additionally, 65% of dogs and 44% of cats handled chemotherapy better than expected.
289
What types of cells do anticancer agents primarily target?
Rapidly dividing neoplastic cells and some rapidly dividing normal cells, such as villus epithelium and bone marrow cells
## Footnote
This can lead to toxicity.
290
What is the therapeutic index of most anticancer agents?
Most anticancer agents have low therapeutic indices, meaning they have narrow therapeutic-to-toxic ratios.
291
How do anticancer agents follow first-order kinetic principles?
The fraction of cells killed is directly proportional to the dose used
## Footnote
Increasing the dose increases the proportion of neoplastic cells killed but also enhances toxicity.
292
What are the most common toxicities encountered in practice from chemotherapy?
Myelosuppression and gastrointestinal signs
## Footnote
These are due to the rapid division of bone marrow and villal epithelial cells.
293
What are some rare complications of chemotherapy?
Anaphylactoid reactions, dermatologic toxicity, pancreatitis, cardiotoxicity, pulmonary toxicity, neurotoxicity, hepatopathies, and urotoxicity.
294
Fill in the blank: The common toxicities of anticancer drugs are primarily due to their effect on _______.
rapidly dividing cells.
295
What is hyperpigmentation and in which animals is it common during chemotherapy?
Hyperpigmentation is common in dogs receiving doxorubicin- and bleomycin-containing protocols.
## Footnote
It is uncommon in dogs and extremely rare in cats receiving chemotherapy.
296
What percentage of dogs receiving Tanovea develop dermatologic toxicity?
Up to 45% of dogs.
## Footnote
Dermatologic toxicity includes pruritic, focal otitis externa or focal erythemic skin lesions.
297
What are the common clinical signs of pancreatitis in dogs receiving chemotherapy?
Anorexia, vomiting, and depression.
## Footnote
Physical examination findings are often unremarkable, and abdominal pain is rare.
298
Which chemotherapeutic agents have been implicated in pancreatitis in dogs?
L-asparaginase, cyclophosphamide, vincristine, cytosine arabinoside, and doxorubicin.
## Footnote
Reports of pancreatitis in cats are not noted.
299
What are the two types of doxorubicin-induced cardiac toxicities observed in dogs?
Acute reaction during administration and chronic cumulative toxicity.
## Footnote
Acute toxicity includes cardiac arrhythmias; chronic toxicity can lead to dilated cardiomyopathy.
300
What is the hallmark of chronic doxorubicin toxicity in dogs?
Dilated cardiomyopathy after exceeding a total cumulative dose of approximately 240 mg/m2.
## Footnote
Histologic lesions include vacuolation of myocytes.
301
What is a recommended precaution for dogs receiving drugs that may cause pancreatitis?
Feeding a low-fat diet.
## Footnote
This may help in minimizing risks.
302
What are the potential nephrotoxic agents in chemotherapy for dogs?
Doxorubicin, cisplatin, and intermediate to high doses of methotrexate.
## Footnote
Nephrotoxicity is rarely observed, particularly in dogs.
303
What is sterile hemorrhagic cystitis (SHC) and what causes it?
A complication of long-term cyclophosphamide therapy caused by the caustic effects of cyclophosphamide metabolites on the bladder epithelium.
## Footnote
Clinical signs include pollakiuria, hematuria, and dysuria.
304
What are the clinical signs of hepatotoxicity associated with chemotherapy in dogs?
Marked increases in alanine transaminase (ALT) and mild increases in alkaline phosphatase (ALP).
## Footnote
Hepatotoxicity is extremely rare in dogs and cats.
305
What is the neurotoxic effect of 5-FU in dogs?
Excitation and cerebellar ataxia, resulting in death in approximately one third of dogs.
## Footnote
Neurotoxicity is common in cats.
306
What is a rare pulmonary toxicity associated with lomustine in cats?
Development of pulmonary fibrosis.
## Footnote
This can occur after a high cumulative dose.
307
What is acute tumor lysis syndrome?
A syndrome of hyperuricemia, hyperphosphatemia, and other metabolic disturbances following rapid tumor cell lysis.
## Footnote
This condition is often seen in human patients.
308
True or False: Cardiotoxicity from doxorubicin is common in cats.
False.
## Footnote
It is extremely rare in cats.
309
Fill in the blank: Doxorubicin-induced cardiac arrhythmias can be prevented by pretreatment with _______.
H1 and H2 antihistamines.
310
What is the recommended frequency for echocardiographic evaluation in high-risk dogs receiving doxorubicin?
Every three doxorubicin cycles (9 weeks).
311
What is the role of dexrazoxane in chemotherapy?
It reduces chronic cardiotoxicity induced by doxorubicin.
312
What are the clinical signs of sterile hemorrhagic cystitis?
Pollakiuria, hematuria, dysuria.
## Footnote
Urinalysis typically reveals blood and increased white blood cells.
313
What should be done if clinical signs of nephrotoxicosis develop in dogs receiving doxorubicin?
Consider discontinuation of doxorubicin.
314
What is the potential concern of using Bleomycin in veterinary medicine?
Pulmonary toxicity
## Footnote
Bleomycin has been associated with pulmonary toxicity in humans, which raises concerns for its use in animals.
315
Why is cisplatin contraindicated for use in cats?
It can cause fatal pulmonary hypertension and edema
## Footnote
Cisplatin is known to have severe adverse effects in cats, making it unsafe for use.
316
What is acute tumor lysis syndrome (ATLS)?
A syndrome of hyperuricemia, hyperphosphatemia, and hyperkalemia due to rapid lysis of tumor cells
## Footnote
ATLS occurs shortly after chemotherapy, particularly in lymphoma patients.
317
What intracellular concentrations are higher in human lymphoma and leukemic cells compared to normal lymphocytes?
Phosphorus
## Footnote
The concentration of phosphorus in these tumor cells is 4 to 6 times higher than in normal lymphocytes.
318
What are the clinical signs of acute tumor lysis syndrome in dogs?
Depression, vomiting, diarrhea
## Footnote
These signs occur within hours of starting chemotherapy.
319
In which species is ATLS rare?
Cats
## Footnote
ATLS has been primarily reported in dogs undergoing treatment for lymphoma.
320
What factors were noted in the cases of canine ATLS documented in a clinic?
High pretreatment serum creatinine concentrations, high tumor burden, high liver enzyme activities
## Footnote
These factors were present in most of the documented cases.
321
How soon after chemotherapy did clinical signs develop in affected dogs with ATLS?
Within 1 to 7 days
## Footnote
Clinical signs like lethargy, vomiting, and bloody diarrhea were observed during this timeframe.
322
What was the outcome of aggressive fluid therapy in dogs with ATLS?
Resolution of clinical signs in 6 dogs within 3 days
## Footnote
However, 2 dogs died as a result of ATLS despite treatment.
323
What is the main electrolyte disturbance associated with ATLS?
Hyperphosphatemia
## Footnote
This is usually present with or without azotemia, hyperkalemia, hypocalcemia, and metabolic acidosis.
324
What should dogs and cats undergoing chemotherapy be up to date on?
Vaccines
## Footnote
It is controversial whether the use of modified-live vaccines should be avoided due to potential illness in immunosuppressed animals.
325
What is the most effective way to prevent severe, life-threatening sepsis or bleeding due to myelosuppression in chemotherapy patients?
Hematologic monitoring
## Footnote
Complete blood counts (CBCs) should be obtained weekly or bi-weekly.
326
What should be done if the neutrophil count decreases to fewer than 1000 cells/µL?
Temporarily discontinue or decrease the dose of the myelosuppressive agent
## Footnote
Platelet counts below 50,000 cells/µL also warrant similar action.
327
How should neutropenic febrile patients be managed?
Aggressively
## Footnote
Fever in a neutropenic patient is a medical emergency.
328
What is the protocol for managing a neutropenic febrile patient?
1. Physical examination
2. Aseptic IV catheter placement
3. Administer IV fluids
4. Discontinue anticancer agents
5. Obtain blood samples for CBC and biochemical profile
6. Start empirical antibiotic therapy
## Footnote
Corticosteroids should be gradually discontinued if at all.
329
Which antibiotics are commonly used for neutropenic patients?
Enrofloxacin and ampicillin or ampicillin/sulbactam
## Footnote
These agents are effective against common bacterial isolates in such animals.
330
What is the prevalence of bacteremia in neutropenic episodes in dogs undergoing chemotherapy?
12.3%
## Footnote
This was observed in a study of 57 neutropenic episodes.
331
How should neutropenic afebrile patients be treated?
Discontinue drugs and administer antibiotics
## Footnote
Antibiotics include ST, CLAV, or enrofloxacin.
332
What is the recommended dosage for enrofloxacin in neutropenic patients?
5-10 mg/kg PO q24h
## Footnote
This dosage is for treating neutropenic patients.
333
What can alleviate myelosuppression in dogs?
Lithium carbonate or recombinant human G-CSF
## Footnote
G-CSF is typically reserved for patients with accidental chemotherapy overdoses.
334
What are the two major types of gastrointestinal complications in pets receiving chemotherapy?
Anorexia and gastroenterocolitis
## Footnote
Nausea and vomiting are also common.
335
Which drugs are commonly associated with nausea and vomiting in pets?
Dacarbazine, cisplatin, doxorubicin, methotrexate, actinomycin D, cyclophosphamide, 5-fluorouracil
## Footnote
These drugs are known to induce gastrointestinal toxicity.
336
What is the preferred antiemetic for managing chemotherapy-associated nausea in dogs?
Maropitant
## Footnote
Other options include ondansetron and metoclopramide.
337
What is a common complication of doxorubicin administration in susceptible dog breeds?
Doxorubicin-induced enterocolitis
## Footnote
Breeds such as Collies and Old English Sheepdogs are particularly susceptible.
338
What are the clinical signs of hypersensitivity reactions to anticancer agents in dogs?
Head shaking, urticaria, erythema, vomiting, diarrhea, hypotension
## Footnote
These signs appear during or shortly after administration.
339
What should be administered to prevent systemic anaphylactic reactions during chemotherapy?
H1 antihistamines
## Footnote
Diphenhydramine is commonly used before drug administration.
340
What is the treatment for acute hypersensitivity reactions?
Discontinue the agent and administer H1 antihistamines, dexamethasone, and fluids
## Footnote
Epinephrine may be used for severe reactions.
341
What is the recommended dosage of diphenhydramine for mild systemic reactions?
0.2-0.5 mg/kg by slow IV infusion
342
What is the recommended dosage of dexamethasone sodium phosphate for severe systemic reactions?
1-2 mg/kg IV
343
What should be administered for severe systemic reactions?
Epinephrine (0.1-0.3 mL of a 1:1000 solution intramuscularly or intravenously)
344
Should injectable H1 antihistamines be used in cats?
With caution, as they can cause acute central nervous system depression leading to apnea
345
What are the three types of dermatologic toxicities that can occur in small animals due to anticancer agents?
* Local tissue necrosis (caused by extravasation) * Delayed hair growth and alopecia * Hyperpigmentation
346
What is a unique dermatologic toxicity associated with rabacfosadine?
347
What is a common result of extravasation of chemotherapeutic agents like vincristine and doxorubicin?
Local tissue necrosis
348
Which breeds are mentioned as experiencing pruritus or discomfort around the IV injection site?
* Labrador Retrievers * Golden Retrievers
349
What can be applied to prevent licking and the development of pyotraumatic dermatitis after IV injection?
A bandage or an Elizabethan collar
350
What gauge catheters are recommended to administer caustic drugs?
* 22- to 23-gauge indwelling IV catheters * 23- to 25-gauge butterfly catheters
351
What is the recommended dilution for vincristine and doxorubicin before administration?
* Vincristine to a final concentration of 0.1 mg/mL * Doxorubicin to a concentration of 0.5 mg/mL
352
What is the consequence of perivascular administration of doxorubicin?
Severe tissue necrosis
353
What is the dose of dexrazoxane recommended for management of doxorubicin extravasation?
5 to 10 times the dose of doxorubicin given
354
What are the clinical signs of extravasation?
* Pain * Pruritus * Erythema * Moist dermatitis * Necrosis
355
What is more common in dogs and cats undergoing chemotherapy, delayed hair growth or alopecia?
Delayed hair growth
356
Which breeds are predominantly affected by chemotherapy-induced alopecia?
* Poodles * Schnauzers * Kerry Blue Terriers
357
What drugs are commonly associated with delayed hair growth and alopecia?
* Cyclophosphamide * Doxorubicin * 5-FU * 6-thioguanine * Hydroxyurea
358
What typically happens to alopecia and delayed hair growth after discontinuation of the offending agent?
They usually resolve shortly after
359
What is the first step in evaluating a solitary mass in a dog or cat?
Perform a fine-needle aspiration (FNA) for cytologic evaluation
## Footnote
This is a simple, atraumatic, quick, and inexpensive procedure that helps in diagnosing the mass.
360
What are the four possible approaches when a mass is found during a physical examination?
* Do nothing and see if the mass goes away
* Evaluate the mass cytologically
* Evaluate the mass histopathologically
* Do a complete workup including CBC, serum biochemistry, radiography, abdominal ultrasonography, and urinalysis
361
True or False: Most masses regress spontaneously.
False
## Footnote
Most masses, except for certain inflammatory lesions and histiocytomas in young dogs, do not regress spontaneously.
362
What should be done if a cytologic diagnosis of a benign neoplasm is made?
Options include: * Do nothing and observe the mass * Surgically excise it
363
What is the recommendation if a benign neoplasm is diagnosed?
Adopt a wait-and-see attitude
## Footnote
Measure the mass and record its size; excision is recommended if it enlarges, becomes inflamed, or ulcerates.
364
What additional evaluation is warranted if a cytologic diagnosis of malignancy is obtained?
Thoracic radiographs to search for metastatic disease
## Footnote
Two lateral views and a ventrodorsal view are recommended.
365
What is a common finding in dogs with mediastinal lymphoma?
Hypercalcemia
366
Fill in the blank: A ___________ is a procedure used to obtain a sample of cells from a mass for cytologic evaluation.
fine-needle aspiration (FNA)
367
What is the typical age of presentation for anterior mediastinal lymphomas in cats?
1-3 years old
368
What is the typical age of presentation for thymomas in cats?
Older than 8 years old
369
What is the primary diagnostic tool for evaluating a mediastinal mass?
Transthoracic fine-needle aspiration (FNA)
370
What is the significance of performing a complete workup (option 4) for a solitary mass?
Rarely provides additional diagnostic information regarding the mass
371
What type of tumors are most commonly associated with anterior mediastinal masses in small animals?
* Lymphomas
* Thymomas
372
What should be considered before recommending specific treatment for an anterior mediastinal mass?
Tumor type and potential for surgical excision or chemotherapy
373
What are the common paraneoplastic syndromes associated with thymoma in dogs and cats?
* Generalized or focal myasthenia gravis
* Polymyositis
* Exfoliative dermatitis
* Lymphocytosis
* Neutropenia
374
What is the typical appearance of thymomas on ultrasonography?
Mixed echogenicity with discrete hypoechoic to anechoic areas
375
What is the usual outcome for dogs and cats with metastatic lesions and good quality of life?
Survival times in excess of 6 months are common
376
True or False: Euthanasia is frequently recommended for pets with metastatic lesions.
False
## Footnote
Euthanasia is almost never recommended in dogs and cats with metastatic lesions who maintain a good quality of life.
377
What is the recommended imaging technique to evaluate for metastatic disease in dogs and cats with malignant neoplasms?
Thoracic radiographs
378
What is a common diagnostic technique for detecting metastatic lung lesions?
Percutaneous fine-needle aspiration (FNA)
379
What is the typical consequence of performing a blind percutaneous lung aspirate?
Possible complications include pneumothorax and bleeding
380
What should be done if a lung FNA fails to yield a diagnostic sample?
Consider a lung biopsy under ultrasonographic, fluoroscopic, or CT guidance
381
What is the typical age of dogs diagnosed with anterior mediastinal masses?
Older than 5-6 years
382
What is the most common finding in pleural effusion associated with lymphoma?
Neoplastic cells are often present
383
How does the echogenicity of lymphomas differ from that of thymomas on ultrasonography?
Lymphomas usually appear hypoechoic to anechoic, while thymomas have mixed echogenicity
384
What imaging technique may help in planning surgery for patients with thymoma?
Thoracic CT scan
385
What technique constitutes a relatively safe and reliable evaluation for AMMs?
Transthoracic FNA
386
What gauge needle is typically used for sampling the mass in transthoracic FNA?
25-gauge needle
387
What imaging methods can guide the transthoracic FNA procedure?
* Radiography
* Fluoroscopy
* Ultrasonography
* CT
388
What is the risk of postaspiration bleeding during transthoracic FNA?
Extremely rare
389
What are the cytological characteristics of mediastinal lymphomas?
* Monomorphic population of lymphoid cells
* Mostly immature cells
* Low nuclear-to-cytoplasmic ratio
* Dark blue cytoplasm
* Clumped chromatin pattern
* Nucleoli
390
In cats, how do the cells in anterior mediastinal lymphomas generally appear?
Heavily vacuolated and resemble human Burkitt lymphoma cells
391
What is the composition of thymomas cytologically?
* Heterogeneous population
* Small lymphocytes
* Occasionally large blasts
* Epithelial-like cells
392
What are Hassall corpuscles and how often are they seen in cytologic preparations?
Rarely seen
393
What is a characteristic finding in flow cytometry for thymomas?
>10% lymphocytes that are CD4+/CD8+
394
What is the typical treatment for anterior mediastinal lymphomas?
Chemotherapy
395
What additional treatment can be used with chemotherapy for anterior mediastinal lymphomas?
Radiotherapy
396
What was reported about the survival of dogs that underwent radiotherapy in a recent study?
Prolonged progression-free survival and overall survival
397
What must be ensured before considering radiotherapy in animals?
The animal must be deemed an appropriate candidate for anesthesia
398
What is the typical outcome of surgical excision for most thymomas?
Usually curative
399
What was the median survival time for dogs with thymomas in a review?
18.5 months
400
Can radiotherapy achieve long-lasting remission in thymoma patients?
Rarely achieved
401
What is a potential issue with chemotherapy for thymomas?
May only eliminate the lymphoid cell population
402
What are the two therapeutic options if a definitive diagnosis of thymoma or lymphoma cannot be obtained preoperatively?
* Perform a thoracotomy and excise the mass
* Initiate chemotherapy for lymphoma
403
What should be considered if no remission is observed 10 to 14 days after starting chemotherapy?
Surgical resection should be considered
404
What is lymphoma?
A lymphoid malignancy that originates from solid organs or tissues.
405
What distinguishes lymphomas from lymphoid leukemias?
Lymphomas originate from solid organs or tissues, while lymphoid leukemias originate in the bone marrow.
406
What percentage of cats with lymphoma are persistently infected with feline leukemia virus (FeLV)?
Approximately 70%.
407
How does FeLV infection prevalence differ between young and older cats with lymphoma?
Young cats are generally FeLV positive, whereas older cats are FeLV negative.
408
What has been observed about the prevalence of FeLV infection in cats with lymphoma in the United States?
It has been decreasing.
409
What is the risk factor for lymphoma associated with feline immunodeficiency virus (FIV)?
Cats infected with FIV are almost six times more likely to develop lymphoma than noninfected cats.
410
What is the association of co-infection with FeLV and FIV in relation to lymphoma risk?
Cats co-infected with FeLV and FIV are more than 75 times more likely to develop lymphoma than noninfected cats.
411
Which breeds of dogs have a higher prevalence of T-cell tumors?
Boxers, Shih Tzus, and Siberian Huskies.
412
Which breeds of dogs have predominantly B-cell lymphoma?
Cocker Spaniels and Basset Hounds.
413
What is the bimodal age distribution for cats with lymphoma?
First peak at approximately 2 years, second peak at approximately 10 to 12 years.
414
What are the four anatomic forms of presentation for lymphoma in dogs and cats?
* Multicentric
* Mediastinal
* Alimentary
* Extranodal
415
Which form of lymphoma is most common in dogs?
Multicentric lymphoma.
416
Which form of lymphoma is most common in cats?
Alimentary lymphoma.
417
What are common clinical signs of multicentric lymphoma in dogs and cats?
* Generalized lymphadenopathy
* Weight loss
* Anorexia
* Lethargy
418
What physical examination findings are typical in dogs with multicentric lymphoma?
* Marked to massive generalized lymphadenopathy
* Hepatomegaly
* Splenomegaly
* Extranodal lesions
419
What clinical signs are associated with mediastinal lymphoma?
* Dyspnea
* Coughing
* Dysphagia/regurgitation
420
What are common gastrointestinal signs in cats and dogs with alimentary lymphoma?
* Anorexia
* Vomiting
* Diarrhea
* Weight loss
421
What are common clinical signs of extranodal lymphomas?
Variable, depending on the location of lesions.
422
What is a characteristic lesion of cutaneous lymphoma in dogs?
A circular, raised, erythematous, donut-shaped, dermoepidermal mass.
423
What is the typical presentation of renal lymphoma in cats?
* Emaciation
* Pale mucous membranes
* Large, irregular, firm kidneys
424
What neurological signs might indicate neural lymphoma?
Variety of neurologic signs reflecting the location and extent of the neoplasm.
425
What is a common paraneoplastic syndrome in dogs with lymphoma?
Hypercalcemia.
426
What hematologic abnormalities can occur in patients with lymphoma?
* Nonregenerative anemia
* Leukocytosis
* Neutrophilia
* Monocytosis
* Eosinophilia
* Thrombocytopenia
427
What is the most common serum biochemical abnormality in dogs with lymphoma?
Hypercalcemia.
428
What is the mechanism believed to underlie hypercalcemia in dogs with lymphoma?
Production of a parathyroid hormone-like protein (PTHrP) by neoplastic cells.
429
What is hypercalcemia in dogs with lymphoma primarily associated with?
Production of a parathyroid hormone-like protein called PTHrP
## Footnote
Hypercalcemia occurs in approximately 20% to 40% of dogs with lymphoma, particularly those with T-cell origin.
430
What is a rare paraneoplastic abnormality that can occur in cats and dogs with lymphoma?
Hyperproteinemia
## Footnote
It may be secondary to the production of a monoclonal protein by the lymphoma cells.
431
What is the most common paraneoplastic abnormality in dogs with lymphoma?
Hypercalcemia
## Footnote
It is extremely rare in cats and is more prevalent in dogs with mediastinal lymphoma.
432
What are the common hematologic abnormalities seen in cats and dogs with lymphoma?
* Nonregenerative anemia
* Leukocytosis
* Neutrophilia (with or without a left shift)
* Monocytosis
* Eosinophilia (usually in cats)
* Thrombocytopenia
* Isolated or combined cytopenias
* Leukoerythroblastic reactions
## Footnote
Lymphocytosis is rare and usually of low magnitude.
433
What imaging abnormalities are typically observed in cats and dogs with lymphoma?
Lymphadenopathy or organomegaly (e.g., hepatomegaly, splenomegaly, renomegaly)
## Footnote
Occasionally, infiltration of other organs may lead to additional radiographic abnormalities.
434
What are the typical radiographic changes in multicentric lymphoma in cats and dogs?
* Sternal or tracheobronchial lymphadenopathy
* Interstitial, bronchoalveolar, or mixed pulmonary infiltrates
* Intraabdominal lymphadenopathy (e.g., mesenteric or iliac)
* Hepatomegaly
* Splenomegaly
* Renomegaly
* Intraabdominal masses
## Footnote
Rarely, lytic or proliferative bone lesions are identified on radiographs.
435
True or False: Hypercalcemia is more common in cats with lymphoma than in dogs.
False
## Footnote
Hypercalcemia is extremely rare in cats with lymphoma.
436
What serum biochemical abnormalities are more common in dogs than in cats with lymphoma?
Hypercalcemia or gammopathies
## Footnote
Serum biochemical abnormalities are significant indicators in diagnosing lymphoma.
437
Fill in the blank: Hyperproteinemia may result in the development of _______.
hyperviscosity syndrome
## Footnote
This is due to the production of a monoclonal protein by lymphoma cells.
438
What is the significance of serum protein electrophoresis in diagnosing lymphoma?
Identifies monoclonal gammopathy
## Footnote
In a study of 155 cats, only one had a monoclonal gammopathy associated with lymphoma.
439
What are the notable serum concentrations identified in dogs with lymphoma and hypercalcemia?
Markedly increased serum concentrations of 1,25-vitamin D
## Footnote
This finding was documented by one of the authors (GC).
440
What is the primary method used to confirm a diagnosis of lymphoma before therapy?
Cytologically, histopathologically, or using molecular techniques.
441
What does a minimum database for lymphoma diagnosis include?
A CBC, serum biochemistry profile, and urinalysis.
442
How are lymphomas classified based on cell size?
Small-cell, intermediate-cell, and large-cell types.
443
What is the general progression characteristic of small-cell lymphomas?
Slowly progressive (indolent).
444
What is the prognosis for large-cell lymphomas?
More aggressive.
445
What percentage of dogs can be diagnosed cytologically with lymphoma?
Over 90%.
446
What percentage of cats can be diagnosed cytologically with lymphoma?
70% to 75%.
447
What has been proposed by Valli et al. regarding lymphoma classification?
A modified system with more than 30 categories of tumors.
448
What are two subtypes of multicentric indolent lymphomas?
* Mantle zone lymphoma (MZL-intermediate cell, B-cell)
* T zone lymphoma (TZL-small cell, T-cell)
449
What is a characteristic feature of marginal zone lymphoma in dogs?
It usually presents as a solitary splenic mass.
450
What are the two major benefits of a cytologic diagnosis over histopathologic evaluation?
* Minimal or no morbidity
* Financially acceptable to most owners.
451
What new diagnostic methodologies are used for lymphoma?
* Immunophenotyping by FCM
* Clonal analysis by PCR.
452
What does immunophenotyping by FCM involve?
Incubating a sample with specific antibodies to recognize T or B cells.
453
What is the purpose of staging lymphoma?
To obtain a prognosis.
454
What staging system is routinely used for lymphoma in cats and dogs?
World Health Organization's staging system.
455
What is a significant prognostic factor in the WHO staging system?
Asymptomatic (substage a) dogs have a better prognosis than sick (substage b) dogs.
456
What is the minimum database to be performed in cats and dogs with lymphoma?
* CBC
* Serum biochemistry profile
* Urinalysis
* FeLV and FIV tests in cats.
457
What is the typical survival time for untreated cats and dogs with lymphoma?
4 to 8 weeks.
458
What is the mainstay treatment for lymphoma?
Chemotherapy.
459
What are the two main chemotherapeutic approaches for lymphoma?
* Induction chemotherapy followed by maintenance
* More aggressive chemotherapy for a finite period.
460
What does the COP-based chemotherapy protocol consist of?
* Cyclophosphamide
* Vincristine
* Prednisone.
461
What is the duration of the induction phase in lymphoma treatment?
6 to 8 weeks.
462
What is the purpose of the maintenance phase in lymphoma treatment?
To monitor and maintain remission after induction.
463
What is a common treatment for dogs with T-cell tumors in the maintenance phase?
Lomustine and prednisone.
464
How often should patients be evaluated during the induction phase?
Weekly.
465
What is the expected survival time for most dogs with lymphoma treated with multiagent chemotherapy?
8 to 16 months.
466
What is the significance of FeLV infection in cats with lymphoma?
It is a negative prognostic factor.
467
What is the diagnostic criterion for CNS lymphoma based on CSF analysis?
High numbers of neoplastic lymphoid cells and increased protein concentration.
468
True or False: Every dog or cat with lymphoma should be immunophenotyped before therapy.
False.
469
What is the expected survival time for cats with small cell intestinal lymphoma?
Exceeds 2 years.
470
What is the typical response rate for cats with multicentric lymphoma treated with chemotherapy?
Approximately 65% to 75%.
471
What is the route of administration for cytosine arabinoside in dogs or cats with CNS or ocular involvement?
Subcutaneous (SC) route or as a continuous rate infusion for 6 to 8 hours
## Footnote
This is part of the COAP protocol
472
What is the duration of the induction phase of chemotherapy for lymphoma in dogs and cats?
6 to 8 weeks
473
What is the dose-limiting toxicity of the induction protocol for lymphoma treatment?
Hematologic toxicity (myelosuppression leading to neutropenia)
474
What percentage of patients experience neutropenia during the induction phase?
Less than 10%
475
When does the neutrophil nadir usually occur during the treatment?
Around day 7 or 8
476
What are the common toxic signs during the induction phase?
Hematologic signs, specifically cytopenias
477
What should be administered if cats develop anorexia while receiving cyclophosphamide?
Cyproheptadine or mirtazapine
478
What is the recommended dosage of capromorelin for cats?
3 mg/kg PO every 24 hours
479
What is the typical frequency of chemotherapy visits during the induction phase?
Weekly
480
What is the name of the maintenance protocol consisting of chlorambucil, methotrexate, and prednisone?
LMP ('lump')
481
What is the main adverse effect associated with methotrexate in the LMP protocol?
Gastrointestinal tract signs (anorexia, vomiting, diarrhea)
482
What is the typical monitoring schedule during the maintenance phase?
Every 6 to 8 weeks
483
What is the typical remission duration for patients treated with the LMP protocol?
Approximately 3 to 6 months
484
What are the main components of the CHOP-based chemotherapy protocol?
Cyclophosphamide, doxorubicin, vincristine, and prednisone
485
What is the typical remission rate for dogs with high-grade lymphoma treated with CHOP-based protocols?
Approximately 85% to 95%
486
What is the median survival time (MST) reported for dogs with multicentric lymphoma?
10 to 12 months
487
True or False: CHOP-based protocols are associated with longer MSTs for cats compared to dogs.
False
488
What is the purpose of L-asparaginase in lymphoma treatment for dogs?
To induce complete remission in cases of partial remission
489
What is the recommended dosage of L-asparaginase for dogs undergoing induction therapy?
10,000-20,000 IU/m2 IM or SC
490
What is the expected timing for relapse after induction therapy with COP or CHOP?
3 to 6 months after COP and 8 to 9 months after CHOP
491
What is the D-MAC protocol used for?
As an alternative rescue protocol for relapsing lymphoma
492
What drugs are included in the D-MAC protocol?
Dexamethasone, melphalan, cytosine arabinoside, and actinomycin D
493
What percentage of dogs achieve remission with the D-MAC protocol?
Greater than 70%
494
What is the median duration of remission using the D-MAC protocol?
61 days (range 2-467+ days)
495
What should be done if a patient's response to the D-MAC protocol is poor?
Pursue the CHOP protocol
496
What does the CHOP protocol involve?
Two or three cycles of CHOP followed by maintenance chemotherapy
## Footnote
Maintenance includes LMP and possibly vincristine or cytosine arabinoside
497
What is the response rate of single-agent protocols like dacarbazine and CCNU?
Approximately 30% to 40%
## Footnote
Response rates vary based on protocol type
498
What is the response rate of combination protocols such as MOPP and DMAC?
Approximately 60% to 80%
## Footnote
Combination protocols tend to be more effective than single-agent protocols
499
What happens to the probability of remission after subsequent relapses?
It decreases with each relapse, about half of the previous probability
## Footnote
This is often due to the development of multiple-drug resistance
500
What are the common management protocols for indolent lymphomas in dogs?
Chlorambucil and prednisone, with or without vincristine, or short course of COP followed by chlorambucil and prednisone
## Footnote
Survival times of 1 to 2 years are common
501
What is the suggested approach for solitary lymphomas in dogs or cats?
Thorough staging before localized therapy
## Footnote
Localized treatment alone is often inadequate due to systemic disease
502
What should be done if the tumor is easily resectable?
Resect the mass and treat with chemotherapy
## Footnote
This applies if the surgical risk is minimal
503
What is the recommended treatment for dogs and cats with CNS lymphoma?
Multiple-agent chemotherapy with or without radiotherapy
## Footnote
Surgical excision does not provide a therapeutic advantage
504
What is the preferred drug for intrathecal chemotherapy in CNS lymphoma?
Cytosine arabinoside
## Footnote
It is nontoxic and easy to administer
505
What is the typical duration of remission for CNS lymphoma in dogs and cats?
Usually short, often 2 to 4 months
## Footnote
Prolonged remissions of 6-12 months are possible
506
What treatments are available for ocular lymphoma?
Cytosine arabinoside as slow IV drip, lomustine
## Footnote
Preserving the eye may be an option instead of enucleation
507
What is the common treatment for cutaneous lymphoma in dogs?
Standard chemotherapy protocols like COP or CHOP-based protocols
## Footnote
Epitheliotropic T-cell lymphomas may require lomustine-containing protocols
508
What is the response rate for lomustine in treating epitheliotropic cutaneous T-cell lymphoma?
Overall response rate of approximately 80%
## Footnote
20% to 30% attain CR and 50% to 60% attain PR
509
What is the recommended approach for cats with epitheliotropic intestinal lymphoma?
Combination of chlorambucil and prednisolone, or dexamethasone
## Footnote
If no improvement, vincristine can be added
510
What are some low-budget lymphoma protocols for dogs and cats?
Prednisone alone, prednisone and chlorambucil, chlorambucil alone, lomustine alone, or prednisone and lomustine
## Footnote
These options offer prolonged quality survival times despite shorter remissions
511
What are leukemias?
Malignant neoplasms originating from hematopoietic precursor cells in the bone marrow
512
What happens to hematopoietic precursor cells in leukemias?
They are unable to undergo terminal differentiation or apoptosis and self-replicate as clones of usually immature cells
513
What are the terms used for leukemias with neoplastic cells absent in circulation?
Aleukemic and subleukemic
514
How are leukemias classified based on cell line of origin?
Lymphoid and myeloid
515
What are acute leukemias characterized by?
Aggressive behavior and the presence of immature (blast) cells
516
What defines chronic leukemias?
A protracted course with well-differentiated late precursors
517
What is blast transformation in chronic myeloid leukemia (CML)?
When CML behaves like an acute leukemia and is usually refractory to therapy
518
What is Richter syndrome?
Transformation of chronic lymphocytic leukemia (CLL) into an aggressive high-grade lymphoma
519
What challenges exist in classifying acute leukemias in dogs and cats?
Morphological classification is difficult due to similarities in poorly differentiated blasts
520
What diagnostic methods are used to classify leukemic blasts?
Cytochemical stains and immunophenotyping
521
What are common T-lymphocyte markers used in immunophenotyping?
* CD3
* CD4
* CD5 (in cats)
* CD8
522
What are common B-lymphocyte markers used in immunophenotyping?
* CD21
* CD79a
523
How is acute myeloid leukemia (AML) diagnosed in dogs?
Cells negative for lymphoid markers, positive for CD45 and CD34
524
What is the significance of ALP cytochemical staining?
It helps differentiate AML from acute lymphoid leukemia (ALL)
525
What is myelodysplastic syndrome (MDS)?
A syndrome of hematopoietic dysfunction preceding acute myelogenous leukemia
526
What is the leukemia-to-lymphoma ratio in dogs?
Approximately 1:7 to 1:10
527
What is the most common form of acute leukemia in dogs?
Acute myeloid leukemia (AML)
528
What are the clinical signs of acute leukemia in dogs?
* Lethargy
* Anorexia
* Persistent fever
* Severe weight loss
* Shifting limb lameness
529
What hematologic changes are present in dogs with acute leukemia?
* Abnormal cells in peripheral blood
* Cytopenias
* Bicytopenias
* Pancytopenia
530
What is the median WBC count in dogs with ALL?
298,200/µL
531
What diagnostic methods confirm acute leukemia in dogs?
Complete blood count (CBC) and bone marrow aspirate or biopsy
532
What are the differential diagnoses for acute leukemia in dogs?
* Lymphoma
* Malignant histiocytosis
* Systemic mast cell disease
* Infectious diseases
533
What factors contribute to treatment failure in dogs with acute leukemias?
534
What is the WBC count indicative of Acute Lymphoblastic Leukemia (ALL) in dogs?
>500,000/µL, mostly blasts
535
What are the common treatment challenges for dogs with acute leukemias?
* Failure to induce remission
* Failure to maintain remission
* Organ failure from leukemic cell infiltration
* Development of fatal sepsis or bleeding
536
What is the average survival time for dogs with acute leukemias?
8 to 55 days
537
What is the prognosis for dogs with Acute Lymphoblastic Leukemia (ALL) compared to those with lymphoma?
Prognosis is slightly better, but survival times are shorter than in lymphoma
538
What are the remission rates for dogs with ALL?
Approximately 20% to 40%
539
What is the average survival time for dogs treated with chemotherapy for ALL?
1-3 months
540
What is the most common type of chronic leukemia in dogs?
Chronic Lymphocytic Leukemia (CLL)
541
What are common clinical signs of Chronic Lymphocytic Leukemia (CLL) in dogs?
* Lethargy
* Anorexia
* Vomiting
* Mildly enlarged lymph nodes
* Intermittent diarrhea or vomiting
* Weight loss
542
What is Richter syndrome in dogs with CLL?
Development of diffuse large cell lymphoma characterized by massive lymphadenopathy and hepatosplenomegaly
543
What is the most common hematologic abnormality in dogs with CLL?
Marked lymphocytosis resulting in leukocytosis
544
What is the typical lymphocyte count range in dogs with CLL?
8000/µL to more than 100,000/µL
545
What is the diagnostic criterion for Chronic Lymphocytic Leukemia (CLL) in dogs?
Absolute lymphocytosis
546
What hematologic findings are associated with Chronic Myeloid Leukemia (CML) in dogs?
* Leukocytosis with a left-shift
* Anemia
* Thrombocytopenia or thrombocytosis
547
What is the typical treatment outcome for dogs with acute leukemias?
Prolonged remissions are rare and treatment responses are poor
548
True or False: Monoclonal gammopathies are common in dogs with CLL.
False
549
What diagnostic methods can confirm CLL in dogs with lymphocytosis?
* Physical examination findings
* Immunophenotyping
* PCR assay for clonality (PARR)
550
What are the typical clinical signs of Chronic Myeloid Leukemia (CML) in dogs?
Similar to CLL but poorly characterized
551
What is the minimum survival time for untreated dogs with ALL?
Less than 2 weeks
552
Fill in the blank: The most common monoclonal component in CLL is _______.
Immunoglobulin M (IgM)
553
What is the median survival time (MST) for dogs with Richter syndrome?
41 days
554
What is a common consequence of treatment for dogs with acute leukemias?
Sepsis or bleeding during induction
555
What is the prevalence of Chronic Lymphocytic Leukemia (CLL) compared to Chronic Myeloid Leukemia (CML) in dogs?
CLL is far more common than CML
556
What is the first-line treatment for symptomatic dogs with Chronic Lymphocytic Leukemia (CLL)?
Treatment with an alkylator, with or without corticosteroids.
557
What is the dosage of chlorambucil for treating CLL in dogs?
20 mg/m2 given orally once every 2 weeks.
558
When should corticosteroids be added to the treatment for CLL?
When there are paraneoplastic syndromes or the patient is symptomatic.
559
What is the initial dosage of prednisone for dogs with CLL?
50-75 mg/m2 PO q24h for 1 week, then 25 mg/m2 PO q48h.
560
What chemotherapy protocol includes Cyclophosphamide and Vincristine?
COP Protocol.
561
What is the dosage of Cyclophosphamide in the COP Protocol?
200-300 mg/m2 IV or PO once every 2 weeks.
562
What is the role of hydroxyurea in treating Chronic Myelogenous Leukemia (CML)?
It may result in prolonged remission, provided a blast crisis does not occur.
563
What is the typical survival time for dogs with untreated CLL?
More than 2 years.
564
What is the significance of CD34 expression in dogs with neoplastic lymphocytosis?
It is associated with a negative prognosis (survival times of 16 days).
565
How do survival times compare between dogs with B-cell and T-cell proliferations?
Dogs with B-cell proliferation have shorter survival times than those with T-cell (CD8-positive) proliferations.
566
What is the impact of lymphocyte count on survival times in CD8-positive dogs?
Longer survival times if the lymphocyte count is less than 30,000/µL.
567
What is the prognosis for dogs with T-CLL receiving chemotherapy compared to those with B-CLL?
Dogs with T-CLL had approximately 3-fold and 19-fold higher probability of surviving than dogs with B-CLL and atypical CLL, respectively.
568
True or False: Most dogs with CLL die as a result of leukemia-related causes.
False.
569
What is the effect of anemia on survival times in dogs with T-CLL?
Anemic dogs with T-CLL survived a significantly shorter time than dogs without anemia.
570
What is the treatment outcome for blast crises in dogs with CML?
The treatment of blast crises is usually unrewarding.
571
What novel therapeutic approach has shown benefits in humans with CML?
Targeting tyrosine kinase using imatinib (Gleevec).
572
Fill in the blank: The growth fraction of neoplastic lymphocytes in CLL appears to be _______.
low.
573
What is the expected time frame for improvement in hematologic and physical examination abnormalities after treatment for CLL?
More than 1 month, and as long as 6 months.
574
What is the dosage of hydroxyurea for treating CML?
50 mg/kg PO q24h for 1-2 weeks; then q48h.
575
What is the dosage of imatinib for treating CML in dogs?
10 mg/kg PO q24h.
576
What percentage of all hematopoietic neoplasms do true leukemias constitute in cats?
Less than 15%
## Footnote
True leukemias are rare in the feline leukemia virus (FeLV)-free era.
577
What are the classifications of acute leukemias in cats based on cytochemical staining or immunophenotyping?
Approximately two thirds are myeloid and one third are lymphoid
## Footnote
Myelomonocytic leukemias (M4) appear to be rare in cats.
578
What virus is commonly implicated as a cause of leukemias in cats?
Feline leukemia virus (FeLV)
## Footnote
The role of feline immunodeficiency virus (FIV) in the pathogenesis of leukemias is still unclear.
579
What percentage of cats with lymphoid and myeloid leukemias tested positive for FeLV p27?
Approximately 90%
## Footnote
Testing was done using enzyme-linked immunosorbent assay or immunofluorescence.
580
What are common clinical features in cats with acute leukemias?
Similar to those in dogs
## Footnote
Shifting limb lameness and ocular or neurologic signs are less common in cats.
581
What hematologic features are noted in more than three fourths of cats with AML and ALL?
Cytopenias
## Footnote
Leukoerythroblastic reactions are common in AML but rare in ALL.
582
What term do clinical pathologists prefer to refer to leukemia in cats due to changing cytomorphologic features?
Myeloproliferative disorder (MPD)
## Footnote
This reflects the common sequential diagnoses in a given cat.
583
What is the general sequence for diagnosing acute leukemia in cats?
Similar to that for dogs
## Footnote
A bone marrow aspirate can confirm the diagnosis if CBC changes are not diagnostic.
584
What is the range of survival times for cats with ALL treated with multichemotherapy?
1 to 7 months
## Footnote
Cats with ALL have better survival times than those with AML.
585
What is the typical survival time for cats with myeloid leukemias treated with chemotherapy?
2 to 10 weeks, median approximately 3 weeks
## Footnote
Intensive chemotherapy does not appear to be beneficial in cats with acute leukemias.
586
What low-dose treatment has been used as an inductor of differentiation of the neoplastic clone?
Low-dose cytosine arabinoside (LDA)
## Footnote
This treatment has shown good tolerability and minimal toxicity in some studies.
587
What is the average hematocrit level in cats with chronic lymphocytic leukemia (CLL)?
26%
## Footnote
This was observed in a study of FeLV-FIV-negative cats with CLL.
588
What common clinical sign is associated with chronic lymphocytic leukemia (CLL) in cats?
Chronic weight loss
## Footnote
CLL is often found incidentally during routine examinations.
589
What was the response rate of cats treated for CLL with chlorambucil and prednisolone?
86%
## Footnote
The median survival time (MST) for treated cats was 14 months.
590
What is poorly characterized in cats, similar to dogs?
Chronic myeloid leukemia (CML)
## Footnote
CML lacks detailed characterization in feline medicine.
591
What are hemangiosarcomas (HSAs)?
Malignant neoplasms originating from circulating endothelial cell precursors.
592
In which age group and gender are hemangiosarcomas most prevalent in dogs?
Predominantly in older dogs (8-10 years) and in males.
593
Which dog breeds are at high risk for hemangiosarcomas?
German Shepherds and Golden Retrievers.
594
What are the common sites of hemangiosarcoma involvement at the time of presentation?
* Spleen
* Right atrium
* Subcutis
* Retroperitoneal space
595
What percentage of hemangiosarcomas originate in the spleen?
Approximately 50%.
596
What are the clinical signs that may lead to evaluation of dogs with hemangiosarcoma?
* Acute collapse
* Abdominal distention
* Cardiac arrhythmias
597
What is a common cause of acute collapse in dogs with hemangiosarcoma?
Spontaneous rupture of the primary tumor or a metastatic lesion.
598
What are two common problems in dogs with hemangiosarcoma?
* Anemia
* Spontaneous bleeding
599
What is disseminated intravascular coagulation (DIC) commonly associated with in hemangiosarcoma?
Spontaneous bleeding.
600
What hematologic abnormalities are commonly seen in dogs with hemangiosarcoma?
* Anemia
* Thrombocytopenia
* Nucleated red blood cells
* Schistocytes
* Acanthocytes
* Leukocytosis
601
What is the prognosis for dogs with hemostatic abnormalities related to hemangiosarcoma?
Approximately 25% can die as a result of these abnormalities.
602
How can hemangiosarcoma be diagnosed cytologically?
Based on the appearance of fine-needle aspirates (FNAs) or impression smears.
603
What characteristics are seen in neoplastic cells of hemangiosarcoma?
* Spindle-shaped or polyhedral
* Large size (40-50 µm)
* Large nuclei with lacy chromatin
* Bluish gray, vacuolated cytoplasm
604
What is the probability of establishing a cytologic diagnosis of hemangiosarcoma after evaluating effusions?
Less than 25%.
605
True or False: Hemangiosarcoma cells are easy to identify in tissue aspirates but difficult in effusions.
True.
606
What may lead to a false-positive diagnosis of hemangiosarcoma in effusions?
Presence of reactive mesothelial cells that resemble neoplastic cells.
607
Fill in the blank: Hemangiosarcomas are highly aggressive neoplasms with most forms infiltrating and _______ early in the disease.
[metastasizing].
608
What is the primary method to confirm a diagnosis of HSA?
Histopathological confirmation
## Footnote
A presumptive clinical or cytologic diagnosis of HSA should be confirmed histopathologically, if feasible.
609
What should be submitted for thorough evaluation of large splenic HSAs?
Multiple samples or the entire spleen
## Footnote
Due to large size, multiple samples from different morphologic areas are recommended.
610
What percentage of HSA cases show positivity for von Willebrand factor antigen?
Approximately 90%
## Footnote
HSA cells are positive for von Willebrand factor antigen in about 90% of cases.
611
Which marker is positive in up to 100% of HSA cells?
CD31
## Footnote
CD31 is a novel marker that is positive in nearly all HSA cells.
612
What diagnostic imaging techniques can detect metastatic sites in HSA?
Radiography, ultrasonography, computed tomography (CT)
## Footnote
These techniques are used to detect metastases in dogs with HSA.
613
What staging diagnostics should be considered for dogs with HSA?
* Complete blood count (CBC)
* Serum biochemistry profile
* Hemostasis screen
* Urinalysis
* Thoracic radiographs
* Abdominal ultrasonography
* Echocardiography
## Footnote
These diagnostics help assess the extent of HSA in dogs.
614
What is the likelihood of splenic HSA if a dog presents with a splenic mass and a nontraumatic hemoabdomen?
Approximately 50% to 75%
## Footnote
This high probability indicates a strong likelihood of HSA in such cases.
615
What is the probability of HSA if only a splenic mass is present without a hemoabdomen?
Approximately 30%
## Footnote
This suggests that 70% of these lesions are likely benign.
616
What has historically been the main treatment for dogs with HSA?
Surgery
## Footnote
Surgery has been the primary treatment option, but results have been poor.
617
What is the typical survival time after splenectomy for dogs with HSA?
Approximately 20-60 days
## Footnote
The 1-year survival rate after splenectomy alone is less than 10%.
618
What are the two commonly used doxorubicin-based protocols for HSA treatment?
* Dose-intensified doxorubicin protocol
* VAC protocol
## Footnote
These protocols are used in the adjuvant setting for HSA treatment.
619
What is the median survival time (MST) for dogs with stage I disease using the dose-intensified doxorubicin protocol?
8.5 months
## Footnote
This protocol has shown better outcomes compared to surgery alone.
620
What is the MST for dogs with stage III disease undergoing VAC chemotherapy?
6.5 months
## Footnote
Dogs with metastatic disease had comparable or better outcomes than those without metastases.
621
What is the staging system for dogs with splenic HSA?
* Stage I: Disease confined to the spleen
* Stage II: Ruptured splenic HSA
* Stage III: Clinically detectable metastatic HSA; concurrent right atrial mass
## Footnote
This system helps in assessing the progression of the disease.
622
True or False: Concurrent cardiac HSA is common when splenic HSA is first diagnosed.
False
## Footnote
It appears that concurrent cardiac HSA is less common when splenic HSA is diagnosed.
623
What are the typical radiographic findings in dogs with metastatic HSA?
Interstitial or alveolar infiltrates
## Footnote
This pattern differs from the 'cannonball' metastatic lesions seen with other tumors.
624
What is neoadjuvant chemotherapy effective for in dogs?
Soft tissue HSA (e.g., subcutaneous, right atrial)
## Footnote
Neoadjuvant chemotherapy helps in reducing tumor size before surgery.
625
What is the typical outcome of preoperative chemotherapy for HSA?
Marked decrease in tumor size
## Footnote
This makes surgery easier.
626
What type of HSAs are usually cured by surgical excision?
Dermal and conjunctival HSAs
## Footnote
These do not benefit from chemotherapy.
627
What is Yunnan Baiyao?
A traditional Chinese herbal medicine
## Footnote
It has been reported to prolong survival time and help control bleeding in dogs with HSA.
628
What effect does Yunnan Baiyao have on canine HSA cells?
Causes dose and time-dependent HSA cell death through apoptosis
## Footnote
This was shown in studies by Wirth et al., 2016.
629
What is the second supplement proposed for dogs with HSA?
Extract from the common turkey tail mushroom (Coriolous versicolor)
## Footnote
It may delay the progression of metastasis.
630
What is the commercially available product that contains the turkey tail mushroom extract?
I'm-Yunity®
## Footnote
Further investigation into this product is ongoing.
631
How are HSAs usually diagnosed?
On the basis of historical, physical examination, and clinicopathologic findings, alongside ultrasonographic and radiographic changes
## Footnote
A morphologic diagnosis can often be made from cytologic findings.
632
When might histopathology be necessary in diagnosing HSA?
When cytologic findings are inconclusive
## Footnote
This helps in confirming the diagnosis.
633
What is the preferred treatment for HSA in dogs?
Surgery
## Footnote
Surgery is the first line of treatment; however, survival times are generally short.
634
What is recommended for postoperative treatment in dogs with HSA?
Adjuvant chemotherapy using doxorubicin-based protocols
## Footnote
This has been shown to prolong survival times in affected dogs.
635
What are the primary bone neoplasms in dogs?
Relatively common; most are malignant
636
How do primary bone tumors in cats differ from those in dogs?
Most can be cured by wide surgical excision
637
What is the most common primary bone neoplasm in dogs?
Osteosarcoma (OSA)
638
What breeds are primarily affected by osteosarcoma?
Large- and giant-breed dogs, especially Greyhounds
639
What percentage of tumors are appendicular in dogs weighing more than 40 kg?
95%
640
What is the genetic predisposition for osteosarcoma in Greyhounds?
OSA is the most common cause of death (25%) in former racing Greyhounds
641
What characterizes the biologic behavior of osteosarcoma?
Aggressive local infiltration and rapid hematogenous dissemination
642
True or False: OSAs of the axial skeleton have a low metastatic potential.
False
643
Where do appendicular OSAs predominantly occur?
Metaphyses of the distal radius, distal femur, and proximal humerus
644
Which breed commonly has OSA of the distal radius?
Great Danes
645
What is a common reason for Greyhounds to present for veterinary care?
Lameness or swelling of the affected limb
646
What is the typical radiographic pattern of OSAs?
Mixed lytic-proliferative pattern
647
What is a Codman triangle?
A feature developed from adjacent periosteal bone formation
648
What should be performed before deciding on treatment for lytic bone lesions?
Cytology or biopsy specimens
649
What diagnostic imaging is recommended to evaluate the extent of disease after a presumptive diagnosis of OSA?
Thoracic radiographs or CT
650
What percentage of dogs with OSAs have skeletal metastasis?
Less than 10%
651
What is the appearance of OSA cells under cytology?
Round or oval with distinct cytoplasmic borders
652
What is the significance of alkaline phosphatase (ALP) in diagnosing OSA?
Osteoblasts are typically ALP positive
653
Fill in the blank: OSA is the most common cause of death in _______ Greyhounds.
former racing
654
What is the common presentation for dogs with OSA?
Painful swelling in the affected area
655
What is the purpose of a preamputation diagnosis?
To evaluate histopathologic specimens from core biopsies of affected areas
## Footnote
A core biopsy is obtained using a Jamshidi bone marrow biopsy needle under general anesthesia
656
What is the accuracy of cytologic biopsies compared to histopathologic biopsies in diagnosing canine bone lesions?
Approximately 80%
## Footnote
This accuracy extends to the determination of tumor type
657
When should a bone biopsy be pursued?
Only if no cytologic diagnosis can be obtained and a diagnosis is required before treatment consideration
658
What factors allow for limb amputation in the absence of a histopathologic diagnosis?
Understanding of neoplasm behavior and suggestive clinical/radiographic features of OSA
659
What are negative prognostic factors for survival in dogs with OSA?
Presence of pulmonary or lymph node metastases, high serum ALP activity, proximal humeral location
660
What is the standard treatment for dogs with OSA?
Amputation and postoperative adjuvant single-agent or combination chemotherapy
661
What is the median survival time (MST) for dogs with appendicular OSA treated with amputation alone?
Approximately 4 to 6 months
662
What is the MST for dogs treated with amputation and chemotherapy?
12 to 18 months, with approximately 25% living longer than 2 years
663
What chemotherapy drug is typically used immediately after amputation?
Carboplatin
664
What is an alternative therapeutic approach for distal radial or ulnar OSAs?
Limb-sparing surgery with bone resection and replacement with an allograft or prosthetic device
665
What is a major complication of limb-sparing procedures?
Development of osteomyelitis in the allograft, occurring in up to 50% of patients
666
What is stereotactic radiation therapy?
A novel irradiation method delivering high doses to the tumor site while sparing surrounding tissues
667
What is a common complication observed in dogs undergoing stereotactic radiation therapy?
Pathologic fractures in up to 63% of dogs
668
What is the success rate of palliative radiation therapy in relieving pain for dogs?
Approximately 75% for about 2 to 4 months
669
What is a recommended concurrent treatment with palliative radiation therapy?
Bisphosphonates
670
What is the effect of chemotherapy on the biologic behavior of tumors in dogs?
Higher prevalence of bone metastases and lower prevalence of pulmonary metastases
671
What is metastasectomy?
Surgical removal of metastatic nodules after chemotherapy treatment
672
What recent trial evaluated the use of Rapamycin in dogs with OSA?
A multicenter, open label, prospective preclinical trial by the Comparative Oncology Trials Consortium (COTC)
673
What is the treatment of choice for OSAs in cats?
Limb amputation alone
674
What chemotherapy drug is toxic in cats and should not be used?
Cisplatin
675
Fill in the blank: The authors typically use _______ immediately after amputation for dogs with OSA.
carboplatin
676
What does MCT stand for in veterinary medicine?
Mast cell tumor
677
What are the common skin tumors in dogs and cats?
Mast cell tumors (MCTs)
678
From what type of cells do mast cell tumors originate?
Mast cells
679
What substances are contained in mast cells?
* Heparin
* Histamine
* Leukotrienes
* Cytokines
680
Why is the term 'mast cell tumor' preferred over 'mastocytoma' or 'mast cell sarcoma'?
Because of their unpredictable biologic behavior
681
What breeds of dogs are at high risk for mast cell tumors?
* Boxer
* Boston Terrier
* Bull Mastiff
* English Bulldog
* Golden Retriever
682
At what average age do mast cell tumors commonly occur in dogs?
Approximately 8.5 years
683
What is a common clinical feature of mast cell tumors in dogs?
They can occur as dermoepidermal masses or subcutaneous/deep masses
684
What percentage of mast cell tumors in dogs are clinically indistinguishable from lipomas?
Approximately 10% to 15%
685
What is the Darier sign in relation to mast cell tumors?
Erythema and wheal that form after the tumor is slightly traumatized
686
What is the traditional grading system for mast cell tumors in dogs?
Patnaik grading system: grade 1, grade 2, grade 3
687
What is the newer grading system for canine mast cell tumors proposed by pathologists?
Two-tier grading system: low-grade and high-grade
688
What is the median survival time (MST) for dogs with low-grade mast cell tumors?
23 months
689
What is the median survival time (MST) for dogs with high-grade mast cell tumors?
Approximately 4 months
690
What molecular mutation is commonly found in canine mast cell tumors?
Internal tandem duplications in exons 11 and 12 of c-kit
691
What is the relationship between c-kit mutations and tumor grade in mast cell tumors?
More common in high-grade tumors, associated with decreased MST and increased risk of recurrence
692
What is a common complication associated with mast cell tumors due to released bioactive substances?
Gastroduodenal ulceration
693
What is a clinical presentation characteristic of subcutaneous mast cell tumors?
A 'lipoma'-feeling mass
694
What should be included in the evaluation of a dog with suspected mast cell tumor?
FNA of the mass
695
What type of cells are typically found in cytology of mast cell tumors?
Monomorphic population of round cells with prominent intracytoplasmic granules
696
What staining method can be used if granules do not stain with Diff-Quik?
Giemsa or Wright stain
697
True or False: A cytologic diagnosis of a well-differentiated mast cell tumor guarantees a low-grade tumor on histopathology.
False
698
What does a cytologic diagnosis of a well-differentiated MCT imply?
It does not necessarily imply that it will be a low-grade tumor when evaluated histopathologically.
## Footnote
Cytologic grading may not have the same prognostic implications as histopathologic grading.
699
What criteria classify tumors as high grade in the Kiupel grading scheme?
Tumors are classified as high grade if they exhibit:
* Poorly granulated cells
* At least two of the following findings:
* Mitotic figures
* Binucleated or multinucleated cells
* Nuclear pleomorphism
* >50% anisokaryosis
## Footnote
This cytologic grading scheme had 88% sensitivity and 94% specificity relative to histologic grading.
700
What should the clinical evaluation of a dog with a cytologically confirmed MCT include?
It should include:
* Careful palpation of the affected area and draining lymph nodes
* Abdominal palpation, radiography, or ultrasonography
* CBC, serum biochemistry profile, urinalysis
* Thoracic radiography if the neoplasm is in the cranial half of the body
## Footnote
This helps to detect intrathoracic lymphadenopathy.
701
What are some negative prognostic factors in dogs with MCT?
Negative prognostic factors include:
* Enlarged regional lymph node
* MCT in high risk locations
* Ulcerated MCT
* History of rapid growth
* Known recurrence of previous MCT
* Systemic signs indicating dissemination
* Certain breeds like Shih Tzus and Rottweilers
## Footnote
These breeds have a higher prevalence of high-grade MCTs.
702
What is the recommendation for FNA of enlarged lymph nodes or organs in the presence of lymphadenopathy, hepatomegaly, or splenomegaly?
FNA should be performed to detect mast cells for diagnosis.
## Footnote
This helps distinguish local neoplasm from metastatic tumor or SMCD.
703
Are buffy coat smears clinically useful in detecting circulating mast cells in dogs?
No, they are not clinically useful.
## Footnote
Most dogs with mastocythemia have inflammatory disorders or other tumors, not MCTs.
704
What is the general rule for staging diagnostics in dogs with solitary MCTs?
Routine staging diagnostics are not considered mandatory unless there are negative prognostic indicators.
## Footnote
Regional lymph node aspiration is the exception.
705
What are the potential treatment options for dogs with MCT?
Treatment options include:
* Surgery
* Radiotherapy
* Chemotherapy
* Molecular-targeted therapy
* Combination of these
## Footnote
Surgery and radiotherapy are potentially curative; chemotherapy is generally palliative.
706
What is the ideal treatment for a solitary MCT in a location amenable to surgical excision?
Aggressive en bloc resection with 2- to 3-cm margins.
## Footnote
If complete excision is confirmed, further treatment is usually unnecessary.
707
What options are available if the excision of an MCT appears incomplete?
Options include:
* Perform a second surgery
* Irradiate the surgical site
* Administer a short course of chemotherapy
## Footnote
These options have approximately an 80% probability of long-term survival.
708
What is the success rate of radiotherapy for treating localized grade 1 or 2 MCT?
Approximately two-thirds of dogs are cured.
## Footnote
Radiotherapy is also recommended for tumors in high-risk areas.
709
What is the purpose of neoadjuvant chemotherapy in MCT treatment?
To decrease tumor size before surgery.
## Footnote
A combination of vinblastine and prednisone can be used.
710
What is the prognosis for dogs with metastatic or disseminated MCTs?
A cure is rarely obtained, except for certain grade II, low-mitotic index MCTs.
## Footnote
Treatment usually consists of chemotherapy and supportive care.
711
What chemotherapy protocol is often recommended for nonsurgical or disseminated MCTs?
An alternating chemotherapy protocol including vinblastine, lomustine, and prednisone.
## Footnote
This protocol has a 50% to 70% response rate.
712
What is a common adverse effect associated with lomustine administration?
Hepatotoxicity.
## Footnote
It is a relatively frequent complication, especially when combined with vinblastine.
713
What is the effectiveness of small molecule TKIs in treating canine MCTs?
They are effective in approximately 40% of MCTs and up to 90% of MCTs with c-kit mutations.
## Footnote
Toceranib and masitinib are examples of TKIs used in treatment.
714
What are common adverse effects of small molecule TKI therapy in dogs?
Adverse effects include:
* Anorexia
* Vomiting
* Diarrhea
## Footnote
These effects are dose-dependent and can affect up to 50% of dogs.
715
What is the median age of cats with Mast Cell Tumors (MCTs)?
10 years old
716
Which breeds of cats may be at higher risk of developing MCTs?
* Siamese
* Burmese
* Russian Blue
* Ragdoll
717
Do feline leukemia virus and feline immunodeficiency virus play a role in the development of MCTs in cats?
No
718
What are the two main forms of feline MCTs?
* Cutaneous MCT
* Visceral mast cell disease
719
What are common clinical signs in cats with visceral MCTs?
* Anorexia
* Vomiting
* Abdominal distention
720
What hematologic abnormalities can be seen in cats with splenic mast cell disease?
* Cytopenias
* Mastocythemia
* Basophilia
* Eosinophilia
721
Which type of MCT is the third most common intestinal tumor in cats?
Intestinal MCT
722
What are the typical initial signs that lead to the evaluation of cats with intestinal MCTs?
* Anorexia
* Vomiting
* Diarrhea
723
Where are cutaneous MCTs typically located in cats?
Primarily in the head and neck regions
724
What are the two classifications of MCTs in cats based on histologic features?
* Mast cell–type MCTs
* Histiocytic-type MCTs
725
What is the treatment approach for cats with solitary cutaneous mass MCTs?
Surgery is indicated
726
What is the survival time for cats with splenic MCTs after splenectomy?
1 to 2 years
727
Which chemotherapeutic agents are commonly used for cats with MCTs?
* Corticosteroids (prednisone, dexamethasone)
* Alkylating agents (chlorambucil, lomustine)
* Vinblastine
* TKIs
728
What is the association between injections/vaccination and sarcomas in cats?
Fibrosarcomas or other types of sarcomas develop in the subcutis or muscle at injection sites
729
What is the estimated incidence of sarcoma development in cats receiving injections?
1 to 2 of 10,000 cats
730
What is the '3, 2, 1 Rule' for diagnosing injection site sarcomas?
* Mass persists for more than 3 months
* Mass is larger than 2 cm in diameter
* Mass grows 1 month after injection
731
What type of biopsy is not recommended prior to definitive treatment for injection site sarcomas?
Excisional biopsies
732
What is the treatment of choice for cats with injection site sarcomas?
Aggressive surgical excision
733
What is the difference in disease-free survival times between aggressive and conservative surgery for injection site sarcomas?
Aggressive surgery: 274 days, Conservative surgery: 66 days
734
What chemotherapy agents may be beneficial for cats with large or incompletely excised tumors?
* Mitoxantrone and cyclophosphamide
* Doxorubicin and cyclophosphamide
* Carboplatin
735
What is the expected response to neoadjuvant chemotherapy in cats with high-grade injection site sarcomas?
Objective responses have been seen
736
True or False: Most fibrosarcomas in cats have a high metastatic potential.
False
